Organic light-emitting device and electronic apparatus including the same

ABSTRACT

Provided are an organic light-emitting device and an electronic apparatus including the same. The organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode and including an emission layer, wherein the emission layer includes a first host and a first dopant, and the first host and the first dopant each satisfy Equations 1-1 and 1-2. In Equations 1-1 and 1-2, T1(H1)onset, T1(D1)onset, T1(H1)max, and T1(D1)max are understood by referring to the description provided herein.T1(H1)onset≥T1(D1)onset  Equation 1-1T1(H1)max≥T1(D1)max.  Equation 1-2

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patent application Ser. No. 16/886,441, filed May 28, 2020, which claims priority to and the benefit of Korean Patent Application No. 10-2019-0064735, filed on May 31, 2019, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference.

BACKGROUND 1. Field

One or more embodiments of the present disclosure relate to an organic light-emitting device and an electronic apparatus including the same.

2. Description of the Related Art

Organic light-emitting devices are self-emission devices that produce full-color images, and also have wide viewing angles, high contrast ratios, short response times, and excellent characteristics in terms of brightness, driving voltage, and response speed, as compared to other devices in the art.

The organic light-emitting device may include a first electrode on a substrate, and a hole transport region, an emission layer, an electron transport region, and a second electrode, which are sequentially on the first electrode. Holes provided from the first electrode may move toward the emission layer through the hole transport region, and electrons provided from the second electrode may move toward the emission layer through the electron transport region. Carriers, such as holes and electrons, recombine in the emission layer to produce excitons. These excitons transit (e.g., transition or relax) from an excited state to a ground state, thereby generating light.

SUMMARY

One or more embodiments include an organic light-emitting device having excellent external quantum efficiency and improved lifespan characteristics and an electronic apparatus including the same.

Additional aspects of embodiments will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

An aspect of embodiments of the present disclosure provides an organic light-emitting device including:

-   -   a first electrode;     -   a second electrode facing the first electrode; and     -   an organic layer between the first electrode and the second         electrode and including an emission layer,     -   wherein the emission layer includes a first host and a first         dopant, and     -   the first host and the first dopant each satisfy Equations 1-1         and 1-2:

T1(H1)_(onset) ≥T1(D1)_(onset)  Equation 1-1

T1(H1)_(max) ≥T1(D1)_(max).  Equation 1-2

In Equations 1-1 and 1-2,

-   -   T1(H1)_(onset) is a triplet energy at an onset wavelength         (λ_(onset)) of the first host,     -   T1(D1)_(onset) is a triplet energy at an onset wavelength of the         first dopant,     -   T1(H1)_(max) is a triplet energy at a maximum emission         wavelength (λ_(max)) of the first host, and     -   T1(D1)_(max) is a triplet energy at a maximum emission         wavelength of the first dopant.

Another aspect of an embodiment of the present disclosure provides an electronic apparatus including: the organic light-emitting device; and a thin-film transistor, wherein the first electrode of the organic light-emitting device is in electrical contact with one of a source electrode and a drain electrode of the thin-film transistor.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of embodiments will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic view of an organic light-emitting device according to an embodiment;

FIG. 2 is a schematic view of an organic light-emitting device according to another embodiment;

FIG. 3 is a schematic view of an organic light-emitting device according to another embodiment;

FIG. 4 is a schematic view of an organic light-emitting device according to another embodiment; and

FIG. 5 schematically illustrates an energy relationship between a first host and a first dopant included in an emission layer of an organic light-emitting device according to an embodiment.

DETAILED DESCRIPTION

The present disclosure will now be described more fully with reference to exemplary embodiments. The disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the disclosure to those skilled in the art. Features of embodiments of the present disclosure, and how to achieve them, will become apparent by reference to the embodiments that will be described herein below in more detail, together with the accompanying drawings. The subject matter of the present disclosure may, however, be embodied in many different forms and should not be limited to the exemplary embodiments.

Hereinafter, embodiments are described in more detail by referring to the attached drawings, and in the drawings, like reference numerals denote like elements, and a redundant explanation thereof will not be repeated herein.

As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It will be further understood that the terms “comprises” and/or “comprising,” as used herein, specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components.

It will be understood that when a layer, region, or component is referred to as being “on” or “onto” another layer, region, or component, it may be directly or indirectly formed on the other layer, region, or component. For example, intervening layers, regions, or components may be present.

Sizes of elements in the drawings may be exaggerated for convenience of explanation. Because sizes and thicknesses of components in the drawings may be arbitrarily illustrated for convenience of explanation, the following embodiments of the present disclosure are not limited thereto.

According to embodiments of the present disclosure, a singlet (S1) energy may be determined by depositing a thin film formed of a target compound to a thickness of 300 Å, cooling the thin film to a low temperature (e.g., 4K), and measuring a photoluminescence spectrum of the thin film by using a photoluminescence measurement apparatus. The photoluminescence spectrum is compared with a general room-temperature photoluminescence spectrum of a thin film of the compound, and peaks observed only at a low temperature are analyzed. In this manner, the singlet (S1) energy is calculated. Unless otherwise defined, the term S1 energy, as used herein, refers to lowest excitation singlet energy.

According to embodiments of the present disclosure, a triplet (T1) energy may be determined by depositing a thin film formed of a target compound to a thickness of 300 Å, cooling the thin film to a low temperature (e.g., 4K), and measuring a photoluminescence spectrum of the thin film by using a photoluminescence measurement apparatus. The photoluminescence spectrum is compared with a general room-temperature photoluminescence spectrum of a thin film of the compound, and peaks observed only at a low temperature are analyzed. In this manner, triplet (T1) energy is calculated. Unless otherwise defined, the term T1 energy, as used herein, refers to a lowest excitation triplet energy.

As used herein, the term “triplet energy at an onset wavelength (λ_(onset))” refers to triplet energy at a position at which the photoluminescence spectrum starts, and the triplet energy is calculated as a triplet energy at a position intersecting with a wavelength axis of a function obtained by plotting the photoluminescence spectrum with a linear function.

The term “organic layer,” as used herein, refers to a single layer and/or a plurality of layers between the anode and the cathode of the organic light-emitting device. A material included in the “organic layer” is not limited to an organic material. For example, the organic layer may include an inorganic material.

The expression “(an organic layer) includes at least one compound” as used herein may include a case in which “(an organic layer) includes identical compounds represented by Formula 1” and a case in which “(an organic layer) includes two or more different compounds represented by Formula 1”.

Description of FIG. 1

FIG. 1 is a schematic cross-sectional view of an organic light-emitting device 10 according to an embodiment. The organic light-emitting device 10 includes a first electrode 110, an organic layer 150, and a second electrode 190.

Hereinafter, the structure of the organic light-emitting device 10 according to an embodiment and a method of manufacturing the organic light-emitting device 10 will be described in connection with FIG. 1 .

Referring to FIG. 1 , there is provided an organic light-emitting device including: a first electrode 110; a second electrode 190 facing the first electrode 110; and organic layer 150 between the first electrode 110 and the second electrode 190,

-   -   wherein the emission layer include a first host and a first         dopant, and     -   the first host and the first dopant each satisfy Equations 1-1         and 1-2:

T1(H1)_(onset) ≥T1(D1)_(onset)  Equation 1-1

T1(H1)_(max) ≥T1(D1)_(max).  Equation 1-2

In Equations 1-1 and 1-2,

-   -   T1(H1)_(onset) is a triplet energy at an onset wavelength         (λ_(onset)) of the first host,     -   T1(D1)_(onset) is a triplet energy at an onset wavelength of the         first dopant,     -   T1(H1)_(max) is a triplet energy at a maximum emission         wavelength (Amax) of the first host, and     -   T1(D1)_(max) is a triplet energy at a maximum emission         wavelength of the first dopant.

Referring to FIG. 5 , because the first host and the first dopant in the organic light-emitting device each satisfy Equations 1-1 and 1-2, triplet energy in the device may be reduced, thereby minimizing or reducing loss of efficiency and improving lifespan characteristics of the device.

In one embodiment, the first host and the first dopant may each satisfy Equation 2-1:

T1(H1)_(max) ≤T1(D1)_(max) ≤T1(H1)_(max)+0.5 eV.  Equation 2-1

In Equation 2-1, T1(H1)_(max) is a triplet energy at a maximum emission wavelength of the first host, and

T1(D1)_(max) is a triplet energy at a maximum emission wavelength of the first dopant.

When the first host in the organic light-emitting device satisfies Equations 2-1 and 2-2, Dexter transfer probability (e.g., Dexter electron transfer) from the triplet energy level (T1(H1)_(max)) of the first host to the triplet energy level (T1(D1)_(max)) of the first dopant is further reduced, thereby improving fluorescence efficiency and lifespan characteristics. As used herein, the terms “Dexter transfer probability” and “Dexter electron transfer” have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs.

First Electrode 110

The first electrode 110 may be formed by depositing or sputtering a material for forming the first electrode 110 on the substrate. When the first electrode 110 is an anode, the material for forming the first electrode 110 may be selected from materials having a high work function to facilitate hole injection.

In FIG. 1 , a substrate may be additionally under the first electrode 110 or above the second electrode 190. The substrate may be a glass substrate or a plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance.

The first electrode 110 may be a reflective electrode, a semi-reflective electrode, or a transmissive electrode. When the first electrode 110 is a transmissive electrode, a material for forming a first electrode may be selected from indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO₂), zinc oxide (ZnO), and any combinations thereof, but embodiments of the present disclosure are not limited thereto. In one or more embodiments, when the first electrode 110 is a semi-transmissive electrode or a reflectable electrode, a material for forming a first electrode may be selected from magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), and any combinations thereof, but embodiments of the present disclosure are not limited thereto.

The first electrode 110 may have a single-layered structure, or a multi-layered structure including two or more layers. For example, the first electrode 110 may have a three-layered structure of ITO/Ag/ITO, but the structure of the first electrode 110 is not limited thereto.

Organic Layer 150

The organic layer 150 is on the first electrode 110. The organic layer 150 may include an emission layer.

The organic layer 150 may further include a hole transport region between the first electrode 110 and the emission layer and an electron transport region between the emission layer and the second electrode 190.

Hole Transport Region in Organic Layer 150

The hole transport region may have i) a single-layered structure including a single layer including a single material, ii) a single-layered structure including a single layer including a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including a plurality of different materials.

The hole transport region may include at least one layer selected from a hole injection layer, a hole transport layer, an emission auxiliary layer, and an electron blocking layer.

For example, the hole transport region may have a single-layered structure including a single layer including a plurality of different materials, or a multi-layered structure having a hole injection layer/hole transport layer structure, a hole injection layer/hole transport layer/emission auxiliary layer structure, a hole injection layer/emission auxiliary layer structure, a hole transport layer/emission auxiliary layer structure, or a hole injection layer/hole transport layer/electron blocking layer structure, wherein for each structure, constituting layers are sequentially stacked from the first electrode 110 in this stated order, but the structure of the hole transport region is not limited thereto.

In one embodiment, the hole transport region may include at least one selected from m-MTDATA, TDATA, 2-TNATA, NPB(NPD), β-NPB, TPD, spiro-TPD, spiro-NPB, methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), a compound represented by Formula 201, and a compound represented by Formula 202:

In Formulae 201 and 202, L₂₀₁ to L₂₀₄ may each independently be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁a cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

L₂₀₅ may be selected from *—O—*′, *—S—*′, *—N(Q₂₀₁)—*′, a substituted or unsubstituted C₁-C₂₀ alkylene group, a substituted or unsubstituted C₂-C₂₀ alkenylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

-   -   xa1 to xa4 may each independently be an integer from 0 to 3,     -   xa5 may be an integer from 1 to 10, and     -   R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be selected from a         substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a         substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a         substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or         unsubstituted C₆-C₆₀ aryloxy group, a substituted or         unsubstituted C₆-C₆₀ arylthio group, a substituted or         unsubstituted C₁-C₆₀ heteroaryl group, a substituted or         unsubstituted monovalent non-aromatic condensed polycyclic         group, and a substituted or unsubstituted monovalent         non-aromatic condensed heteropolycyclic group.

In one embodiment, R₂₀₁ and R₂₀₂ in Formula 202 may optionally be linked to each other via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group, and R₂₀₃ and R₂₀₄ may optionally be linked via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group.

In one or more embodiments, in Formulae 201 and 202,

-   -   L₂₀₁ to L₂₀₅ may each independently be selected from:     -   a phenylene group, a pentalenylene group, an indenylene group, a         naphthylene group, an azulenylene group, a heptalenylene group,         an indacenylene group, an acenaphthylene group, a fluorenylene         group, a spiro-bifluorenylene group, a benzofluorenylene group,         a dibenzofluorenylene group, a phenalenylene group, a         phenanthrenylene group, an anthracenylene group, a         fluoranthenylene group, a triphenylenylene group, a pyrenylene         group, a chrysenylene group, a naphthacenylene group, a         picenylene group, a perylenylene group, a pentaphenylene group,         a hexacenylene group, a pentacenylene group, a rubicenylene         group, a coronenylene group, an ovalenylene group, a         thiophenylene group, a furanylene group, a carbazolylene group,         an indolylene group, an isoindolylene group, a benzofuranylene         group, a benzothiophenylene group, a dibenzofuranylene group, a         dibenzothiophenylene group, a benzocarbazolylene group, a         dibenzocarbazolylene group, a dibenzosilolylene group, and a         pyridinylene group; and     -   a phenylene group, a pentalenylene group, an indenylene group, a         naphthylene group, an azulenylene group, a heptalenylene group,         an indacenylene group, an acenaphthylene group, a fluorenylene         group, a spiro-bifluorenylene group, a benzofluorenylene group,         a dibenzofluorenylene group, a phenalenylene group, a         phenanthrenylene group, an anthracenylene group, a         fluoranthenylene group, a triphenylenylene group, a pyrenylene         group, a chrysenylene group, a naphthacenylene group, a         picenylene group, a perylenylene group, a pentaphenylene group,         a hexacenylene group, a pentacenylene group, a rubicenylene         group, a coronenylene group, an ovalenylene group, a         thiophenylene group, a furanylene group, a carbazolylene group,         an indolylene group, an isoindolylene group, a benzofuranylene         group, a benzothiophenylene group, a dibenzofuranylene group, a         dibenzothiophenylene group, a benzocarbazolylene group, a         dibenzocarbazolylene group, a dibenzosilolylene group, and a         pyridinylene group, each substituted with at least one selected         from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amidino group, a hydrazino group, a         hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a         cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclopentenyl group, a cyclohexenyl group, a phenyl group, a         biphenyl group, a terphenyl group, a phenyl group substituted         with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a         pentalenyl group, an indenyl group, a naphthyl group, an         azulenyl group, a heptalenyl group, an indacenyl group, an         acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group,         a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl         group, a phenanthrenyl group, an anthracenyl group, a         fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a         chrysenyl group, a naphthacenyl group, a picenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a rubicenyl group, a coronenyl group, an         ovalenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂), and     -   Q₃₁ to Q₃a may each independently be selected from a C₁-C₁₀         alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl         group, a terphenyl group, and a naphthyl group.

In one or more embodiments, xa1 to xa4 may each independently be 0, 1, or 2.

In one or more embodiments, xa5 may be 1, 2, 3, or 4.

In one or more embodiments, R₂₀₁, to R₂₀₄ and Q₂₀₁ may each independently be selected from:

-   -   a phenyl group, a biphenyl group, a terphenyl group, a         pentalenyl group, an indenyl group, a naphthyl group, an         azulenyl group, a heptalenyl group, an indacenyl group, an         acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group,         a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl         group, a phenanthrenyl group, an anthracenyl group, a         fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a         chrysenyl group, a naphthacenyl group, a picenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a rubicenyl group, a coronenyl group, an         ovalenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl         group; and     -   a phenyl group, a biphenyl group, a terphenyl group, a         pentalenyl group, an indenyl group, a naphthyl group, an         azulenyl group, a heptalenyl group, an indacenyl group, an         acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group,         a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl         group, a phenanthrenyl group, an anthracenyl group, a         fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a         chrysenyl group, a naphthacenyl group, a picenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a rubicenyl group, a coronenyl group, an         ovalenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl         group, each substituted with at least one selected from         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a         cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclopentenyl group, a cyclohexenyl group, a phenyl group, a         biphenyl group, a terphenyl group, a phenyl group substituted         with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a         pentalenyl group, an indenyl group, a naphthyl group, an         azulenyl group, a heptalenyl group, an indacenyl group, an         acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group,         a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl         group, a phenanthrenyl group, an anthracenyl group, a         fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a         chrysenyl group, a naphthacenyl group, a picenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a rubicenyl group, a coronenyl group, an         ovalenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂), and     -   Q₃₁ to Q₃₃ are the same as described herein above.

In one or more embodiments, at least one selected from R₂₀₁ and R₂₀₃ in Formula 201 may each independently be selected from:

-   -   a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl         group, a dibenzofuranyl group, and a dibenzothiophenyl group;         and     -   a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl         group, a dibenzofuranyl group, and a dibenzothiophenyl group,         each substituted with at least one selected from deuterium, —F,         —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an         amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀         alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a         cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a         cyclohexenyl group, a phenyl group, a biphenyl group, a         terphenyl group, a phenyl group substituted with a C₁-C₁₀ alkyl         group, a phenyl group substituted with —F, a naphthyl group, a         fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group,         a dibenzofuranyl group, and a dibenzothiophenyl group;     -   but embodiments of the present disclosure are not limited         thereto.

In one or more embodiments, in Formula 202, i) R₂₀₁ and R₂₀₂ may be linked to each other via a single bond, and/or ii) R₂₀₃ and R₂₀₄ may be linked to each other via a single bond.

In one or more embodiments, at least one selected from R₂₀₁ to R₂₀₄ in Formula 202 may be selected from:

-   -   a carbazolyl group; and     -   a carbazolyl group substituted with at least one selected from         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a         cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclopentenyl group, a cyclohexenyl group, a phenyl group, a         biphenyl group, a terphenyl group, a phenyl group substituted         with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a         naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a         carbazolyl group, a dibenzofuranyl group, and a         dibenzothiophenyl group,     -   but embodiments of the present disclosure are not limited         thereto.

The compound represented by Formula 201 may be represented by Formula 201A:

In one embodiment, the compound represented by Formula 201 may be represented by Formula 201A(1), but embodiments of the present disclosure are not limited thereto:

In one embodiment, the compound represented by Formula 201 may be represented by Formula 201A-1, but embodiments of the present disclosure are not limited thereto:

In one embodiment, the compound represented by Formula 202 may be represented by Formula 202A:

In one embodiment, the compound represented by Formula 202 may be represented by Formula 202A-1:

In Formulae 201A, 201A(1), 201A-1, 202A, and 202A-1,

-   -   L₂₀₁, to L₂₀₃, xa1 to xa3, xa5, and R₂₀₂ to R₂₀₄ are the same as         described herein above,     -   R₂₁₁ and R₂₁₂ may be understood by referring to the description         provided herein in connection with R₂₀₃,     -   R₂₁₃ to R₂₁₇ may each independently be selected from hydrogen,         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a         cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclopentenyl group, a cyclohexenyl group, a phenyl group, a         biphenyl group, a terphenyl group, a phenyl group substituted         with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a         pentalenyl group, an indenyl group, a naphthyl group, an         azulenyl group, a heptalenyl group, an indacenyl group, an         acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group,         a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl         group, a phenanthrenyl group, an anthracenyl group, a         fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a         chrysenyl group, a naphthacenyl group, a picenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a rubicenyl group, a coronenyl group, an         ovalenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl         group.

The hole transport region may include at least one compound selected from Compounds HT1 to HT46, but embodiments of the present disclosure are not limited thereto:

A thickness of the hole transport region may be in a range of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When the hole transport region includes at least one selected from a hole injection layer and a hole transport layer, the thickness of the hole injection layer may be in a range of about 100 Å to about 9,000 Å, and for example, about 100 Å to about 1,000 Å, and a thickness of the hole transport layer may be in a range of about 50 Å to about 2,000 Å, and for example, about 100 Å to about 1500 Å. When the thicknesses of the hole transport region, the hole injection layer, and the hole transport layer are within these ranges, suitable or satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The emission auxiliary layer may increase luminescence efficiency by compensating for an optical resonance distance according to the wavelength of light emitting by an emission layer, and the electron blocking layer may block or reduce the flow of electrons from an electron transport region. The emission auxiliary layer and the electron blocking layer may include the materials as described herein above.

p-Dopant

The hole transport region may further include, in addition to these materials, a charge-generation material for the improvement of conductive properties. The charge-generation material may be homogeneously or non-homogeneously dispersed in the hole transport region.

The charge-generation material may be, for example, a p-dopant.

In one embodiment, the p-dopant may have a lowest unoccupied molecular orbital (LUMO) energy level of −3.5 eV or less.

The p-dopant may include at least one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but embodiments of the present disclosure are not limited thereto.

In one embodiment, the p-dopant may include at least one selected from:

-   -   a quinone derivative, such as tetracyanoquinodimethane (TCNQ) or         2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ);     -   a metal oxide, such as tungsten oxide or molybdenum oxide;     -   1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN); and     -   a compound represented by Formula 221,     -   but embodiments of the present disclosure are not limited         thereto:

In Formula 221, R₂₂₁ to R₂₂₃ may each independently be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₆₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, wherein at least one selected from R₂₂₁ to R₂₂₃ may have at least one substituent selected from a cyano group, —F, —Cl, —Br, —I, a C₁-C₂₀ alkyl group substituted with —F, a C₁-C₂₀ alkyl group substituted with —Cl, a C₁-C₂₀ alkyl group substituted with —Br, and a C₁-C₂₀ alkyl group substituted with —I.

Emission Layer in Organic Layer 150

When the organic light-emitting device 10 is a full-color organic light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, or a blue emission layer, according to a sub-pixel. In one or more embodiments, the emission layer may have a stacked structure of two or more layers selected from a red emission layer, a green emission layer, and a blue emission layer, in which the two or more layers contact each other or are separated from each other. In one or more embodiments, the emission layer may include two or more materials selected from a red light-emitting material, a green light-emitting material, and a blue light-emitting material, in which the two or more materials are mixed with each other in a single layer to emit white light.

The emission layer may include a first host and a first dopant. The first dopant may be a phosphorous dopant or a fluorescent dopant.

In one embodiment, an amount of the first host included in the emission layer may be greater than that of the first dopant included in the emission layer.

For example, the amount of the first dopant included in the emission layer may be in a range of about 0.01 parts by weight to about 40 parts by weight, for example, 0.01 parts by weight to about 15 parts by weight, based on 100 parts by weight of the host, but embodiments of the present disclosure are not limited thereto.

A thickness of the emission layer may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. When the thickness of the emission layer is within this range, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.

In one embodiment, the emission layer may emit blue light having a maximum emission wavelength of about 440 nm or more and about 490 nm or less.

Host in Emission Layer

In one embodiment, the first host may be a hole transport compound that does not include an electron transport moiety.

The term “electron transport moiety,” as used herein, may include a cyano group, a phosphine oxide group, a sulfone oxide group, a sulfonate group, and/or a π electron-depleted nitrogen-containing ring.

In one embodiment, the first host may form an exciplex with the first dopant.

In one or more embodiments, the emission layer may further include a second host, the first host may be a compound including a hole transport moiety, and the second host may be a compound including an electron transport moiety. For example, the first host and the second host may form an exciplex.

In one embodiment, the first host may be represented by Formula 1, and the second host may be represented by Formula 2:

In Formulae 1 and 2,

-   -   X₁ may be selected from O, S, N(R₃), and C(R₃)(R₄),     -   X₂ may be selected from a single bond, O, S, N(R₅), and         C(R₅)(R₆),     -   ring A₁ and ring A₂ may each independently be selected from a         C₅-C₆₀ carbocyclic group and a C₁-C₆₀ heterocyclic group,     -   R₁ to R₆ may each independently be selected from hydrogen,         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a substituted or unsubstituted C₁-C₆₀ alkyl group, a         substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted         or unsubstituted C₂-C₆₀ alkynyl group, a substituted or         unsubstituted C₁-C₆₀ alkoxy group, a substituted or         unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or         unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or         unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or         unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or         unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted         C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀         arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl         group, a substituted or unsubstituted C₁-C₆₀ heteroaryloxy         group, a substituted or unsubstituted C₁-C₆₀ heteroarylthio         group, a substituted or unsubstituted monovalent non-aromatic         condensed polycyclic group, a substituted or unsubstituted         monovalent non-aromatic condensed heteropolycyclic group,         —Si(Q₁)(Q₂)(Q₃), —B(Q₁)(Q₂), —N(Q₁)(Q₂), —P(Q₁)(Q₂), —C(═O)(Q₁),         —S(═O)(Q₁), —S(═O)₂(Q₁), —P(═O)(Q₁)(Q₂), and —P(═S)(Q₁)(Q₂);     -   a1 and a2 may each independently be selected from 1, 2, 3, 4, 5,         and 6,     -   Q₁ to Q₃ may each independently be selected from hydrogen,         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀         alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,         a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a         C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀         aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl         group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio         group, a monovalent non-aromatic condensed polycyclic group, a         monovalent non-aromatic condensed heteropolycyclic group, a         biphenyl group, and a terphenyl group,     -   X₂₁ may be N or C(R₂₁), X₂₂ may be N or C(R₂₂), X₂₃ may be N or         C(R₂₃), X₂₄ may be N or C(R₂₄), X₂₅ may be N or C(R₂₅), and X₂₆         may be N or C(R₂₆), wherein at least one selected from X₂₁ to         X₂₆ may be N,     -   R₂₁ to R₂₆ may each independently be selected from hydrogen,         deuterium, a substituted or unsubstituted C₆-C₆₀ aryl group, a         substituted or unsubstituted C₁-C₆₀ heteroaryl group, a         substituted or unsubstituted monovalent non-aromatic condensed         polycyclic group, and a substituted or unsubstituted monovalent         non-aromatic condensed heteropolycyclic group, and     -   at least one selected from R₂₁ to R₂₆ May be selected from a         substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or         unsubstituted C₁-C₆₀ heteroaryl group, a substituted or         unsubstituted monovalent non-aromatic condensed polycyclic         group, and a substituted or unsubstituted monovalent         non-aromatic condensed heteropolycyclic group.

In one embodiment, the first host may be represented by Formula 1, and the second host may be represented by Formula 2.

In one embodiment, the emission layer may include a compound represented by Formula 301:

[Ar₃₀₁]_(xb11)—[(L₃₀₁)_(xb1)—R₃₀₁]_(xb21).  Formula 301

In Formula 301, Ar₃₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclic group,

-   -   xb11 may be 1, 2, or 3,     -   L₃₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀         cycloalkylene group, a substituted or unsubstituted C₁-C₁₀         heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀         cycloalkenylene group, a substituted or unsubstituted C₁-C₆₀         heterocycloalkenylene group, a substituted or unsubstituted         C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀         heteroarylene group, a substituted or unsubstituted divalent         non-aromatic condensed polycyclic group, and a substituted or         unsubstituted divalent non-aromatic condensed heteropolycyclic         group,     -   xb1 may be an integer from 0 to 5,     -   R₃₀₁ may be selected from deuterium, —F, —Cl, —Br, —I, a         hydroxyl group, a cyano group, a nitro group, an amidino group,         a hydrazino group, a hydrazono group, a substituted or         unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted         C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀         alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy         group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a         substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a         substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or         unsubstituted C₆-C₆₀ aryloxy group, a substituted or         unsubstituted C₆-C₆₀ arylthio group, a substituted or         unsubstituted C₁-C₆₀ heteroaryl group, a substituted or         unsubstituted monovalent non-aromatic condensed polycyclic         group, a substituted or unsubstituted monovalent non-aromatic         condensed heteropolycyclic group, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃),         —N(Q₃₀₁)(Q₃₀₂), —B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and         —P(═O)(Q₃₀₁)(Q₃₀₂),     -   xb21 may be an integer from 1 to 5, and     -   Q₃₀₁ to Q₃₀₃ may each independently be selected from a C₁-C₁₀         alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl         group, a terphenyl group, and a naphthyl group, but embodiments         of the present disclosure are not limited thereto.

In one embodiment, Ar₃₀₁ in Formula 301 may be selected from:

-   -   a naphthalene group, a fluorene group, a spiro-bifluorene group,         a benzofluorene group, a dibenzofluorene group, a phenalene         group, a phenanthrene group, an anthracene group, a fluoranthene         group, a triphenylene group, a pyrene group, a chrysene group, a         naphthacene group, a picene group, a perylene group, a         pentaphene group, an indenoanthracene group, a dibenzofuran         group, and a dibenzothiophene group; and     -   naphthalene group, a fluorene group, a spiro-bifluorene group, a         benzofluorene group, a dibenzofluorene group, a phenalene group,         a phenanthrene group, an anthracene group, a fluoranthene group,         a triphenylene group, a pyrene group, a chrysene group, a         naphthacene group, a picene group, a perylene group, a         pentaphene group, an indenoanthracene group, a dibenzofuran         group, and a dibenzothiophene group, each substituted with at         least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl         group, a cyano group, a nitro group, an amidino group, a         hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a         C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a         terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),         —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and         —P(═O)(Q₃₁)(Q₃₂),     -   Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀         alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl         group, a terphenyl group, and a naphthyl group, but embodiments         of the present disclosure are not limited thereto.

When xb11 in Formula 301 is 2 or more, two or more Ar₃₀₁(s) may be linked to each other via a single bond.

In one or more embodiments, the compound represented by Formula 301 may be represented by one selected from Formulae 301-1 to 301-3:

In Formulae 301-1 to 301-3, ring A₃₀₁ to ring A₃₀₄ may each independently be selected from a benzene ring, a naphthalene ring, a phenanthrene ring, a fluoranthene ring, a triphenylene ring, a pyrene ring, a chrysene ring, a pyridine ring, a pyrimidine ring, an indene ring, a fluorene ring, a spiro-bifluorene ring, a benzofluorene ring, a dibenzofluorene ring, an indole ring, a carbazole ring, a benzocarbazole ring, a dibenzocarbazole ring, a furan ring, a benzofuran ring, a dibenzofuran ring, a naphthofuran ring, a benzonaphthofuran ring, a dinaphthofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a naphthothiophene ring, a benzonaphthothiophene ring, and a dinaphthothiophene ring,

-   -   X₃₀₁ may be O, S, or N-[(L₃₀₄)_(xb4)—R₃₀₄],     -   R₃₁₁ to R₃₁₄ may each independently be selected from hydrogen,         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl         group, a biphenyl group, a terphenyl group, a naphthyl group         —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),         —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),     -   xb22 and xb23 may each independently be 0, 1, or 2,     -   L₃₀₁ to L₃₀₅ may each independently be selected from a         substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a         substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group,         a substituted or unsubstituted C₆-C₆₀ arylene group, a         substituted or unsubstituted C₁-C₆₀ heteroarylene group, a         substituted or unsubstituted divalent non-aromatic condensed         polycyclic group, and a substituted or unsubstituted divalent         non-aromatic condensed heteropolycyclic group,     -   xb1 to xb4 may be an integer from 0 to 5,     -   xb5 may be an integer from 1 to 5,     -   R₃₀₁ to R₃₀₄ may each independently be selected from deuterium,         —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro         group, an amidino group, a hydrazino group, a hydrazono group, a         substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted         or unsubstituted C₂-C₆₀ alkenyl group, a substituted or         unsubstituted C₂-C₆₀ alkynyl group, a substituted or         unsubstituted C₁-C₆₀ alkoxy group, a substituted or         unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or         unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or         unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or         unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or         unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted         C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀         arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl         group, a substituted or unsubstituted monovalent non-aromatic         condensed polycyclic group, a substituted or unsubstituted         monovalent non-aromatic condensed heteropolycyclic group,         —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂), —B(Q₃₀₁)(Q₃₀₂),         —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂), and     -   Q₃₀₁ to Q₃₀₃ may each independently be selected from a C₁-C₁₀         alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl         group, a terphenyl group, a pentalenyl group, an indenyl group,         a naphthyl group, an azulenyl group, a heptalenyl group, an         indacenyl group, an acenaphthyl group, a fluorenyl group, a         spiro-bifluorenyl group, a benzofluorenyl group, a         dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         naphthacenyl group, a picenyl group, a perylenyl group, a         pentaphenyl group, a hexacenyl group, a pentacenyl group, a         rubicenyl group, a coronenyl group, an ovalenyl group, a         thiophenyl group, a furanyl group, a carbazolyl group, an         indolyl group, an isoindolyl group, a benzofuranyl group, a         benzothiophenyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl         group.

In one embodiment, Ar₃₀₁ in Formula 301 may be a fluorene or a spirobifluorene. For example, the compound represented by Formula 301 may be represented by Formula 301-4 or Formula 301-5:

In Formulae 301-4 and 301-5, Y₃₀₁ and Y₃₀₂ may each independently be a single bond, O, S, N—[(L₃₀₅)_(xb5)—R₃₀₅], or S(═O)₂, and xb5 may be an integer from 1 to 5,

-   -   A₃₀₁ to A₃₀₄, R₃₁₁ to R₃₁₄, xb21 to xb24, L₃₀₁, to L₃₀₄, xb1 to         xb4, and R₃₀₁ to R₃₀₄ may be understood by referring to the         description provided herein,     -   L₃₀₅ may be the same as described in connection with L₃₀₁ to         L₃₀₄, and     -   R₃₀₅ may be the same as described in connection with R₃₀₁ to         R₃₀₄.

In one embodiment, R₃₀₁ in Formula 301 may be amine, for example, —N(Q₃₀₁)(Q₃₀₂). For example, the compound represented by Formula 301 may be represented by Formula 301-6:

In Formula 301-6,

-   -   Ar₃₀₁, xb11, L₃₀₂, xb2, R₃₀₂, xb22, Q₃₀₁, and Q₃₀₂ may be         understood by referring to the description provided herein.

In one embodiment, Ar₃₀₁ in Formula 301 may be a pyridine, a pyrimidine, or a triazine. For example, the compound represented by Formula 301 may be represented by Formula 301-7:

In Formula 301-7, X₃₀₂ may be N or C(R₃₁₁), X₃₀₃ may be N or C(R₃₁₂), and X₃₀₄ may be N or C(R₃₁₃), wherein at least one selected from X₃₀₂ to X₃₀₄ may be N,

-   -   R₃₁₁ to R₃₁₃ may each independently be selected from hydrogen,         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl         group, a biphenyl group, a terphenyl group, a naphthyl group, a         dibenzofuranyl group, a dibenzothiophenyl group, —SH, —S(Q₃₀₁),         —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂), —B(Q₃₀₁)(Q₃₀₂),         —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂),     -   two adjacent substituents among R₃₀₁ to R₃₀₃ and R₃₁₁ to R₃₁₃         may optionally be linked to each other to form a substituted or         unsubstituted C₁-C₆₀ carbocyclic group or a substituted or         unsubstituted C₁-C₆₀ heterocyclic group,     -   L₃₀₁ to L₃₀₃, xb1 to xb3, and R₃₀₁ to R₃₀₃ may be understood by         referring to the description provided herein.

In one embodiment, Ar₃₀₁ in Formula 301 may be a phenanthroline. For example, the compound represented by Formula 301 may be represented by Formula 301-8:

In Formula 301-8,

-   -   R₃₁₁ to R₃₁₃, xb21 to xb23, L₃₀₁ to L₃₀₃, xb1 to xb3, and R₃₀₁         to R₃₀₃ may be understood by referring to the description         provided herein.

In one embodiment, Ar₃₀₁ in Formula 301 may be a diazole or a triazole. For example, the compound represented by Formula 301 may be represented by Formula 301-9:

In Formula 301-9, X₃₀₅ may be N or C(R₃₁₁), X₃₀₆ may be N or C(R₃₁₂), X₃₀₇ may be N or C(R₃₁₃), and X₃₀₈ may be N or C(R₃₁₄), wherein at least one selected from X₃₀₅ to X₃₀₈ may be N,

-   -   R₃₁₁ to R₃₁₄ may each independently be selected from hydrogen,         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl         group, a biphenyl group, a terphenyl group, a naphthyl group, a         dibenzofuranyl group, a dibenzothiophenyl group, —SH, —S(Q₃₀₁),         —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂), —B(Q₃₀₁)(Q₃₀₂),         —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂),     -   two adjacent substituents among R₃₁₁ to R₃₁₄ may optionally be         linked to form a substituted or unsubstituted C₁-C₆₀ carbocyclic         group or a substituted or unsubstituted C₁-C₆₀ heterocyclic         group, and     -   L₃₀₁, xb1, and R₃₀₁ may be understood by referring to the         description provided herein.

For example, L₃₀₁, to L₃₀₅ may each independently be selected from:

-   -   a phenylene group, a naphthylene group, a fluorenylene group, a         spiro-bifluorenylene group, a benzofluorenylene group, a         dibenzofluorenylene group, a phenanthrenylene group, an         anthracenylene group, a fluoranthenylene group, a         triphenylenylene group, a pyrenylene group, a chrysenylene         group, a perylenylene group, a pentaphenylene group, a         hexacenylene group, a pentacenylene group, a thiophenylene         group, a furanylene group, a carbazolylene group, an indolylene         group, an isoindolylene group, a benzofuranylene group, a         benzothiophenylene group, a dibenzofuranylene group, a         dibenzothiophenylene group, a benzocarbazolylene group, a         dibenzocarbazolylene group, a dibenzosilolylene group, a         pyridinylene group, an imidazolylene group, a pyrazolylene         group, a thiazolylene group, an isothiazolylene group, an         oxazolylene group, an isoxazolylene group, a thiadiazolylene         group, an oxadiazolylene group, a pyrazinylene group, a         pyrimidinylene group, a pyridazinylene group, a triazinylene         group, a quinolinylene group, an isoquinolinylene group, a         benzoquinolinylene group, a phthalazinylene group, a         naphthyridinylene group, a quinoxalinylene group, a         quinazolinylene group, a cinnolinylene group, a         phenanthridinylene group, an acridinylene group, a         phenanthrolinylene group, a phenazinylene group, a         benzimidazolylene group, an isobenzothiazolylene group, a         benzoxazolylene group, an isobenzoxazolylene group, a         triazolylene group, a tetrazolylene group, an         imidazopyridinylene group, an imidazopyrimidinylene group, and         an azacarbazolylene group; and     -   a phenylene group, a naphthylene group, a fluorenylene group, a         spiro-bifluorenylene group, a benzofluorenylene group, a         dibenzofluorenylene group, a phenanthrenylene group, an         anthracenylene group, a fluoranthenylene group, a         triphenylenylene group, a pyrenylene group, a chrysenylene         group, a perylenylene group, a pentaphenylene group, a         hexacenylene group, a pentacenylene group, a thiophenylene         group, a furanylene group, a carbazolylene group, an indolylene         group, an isoindolylene group, a benzofuranylene group, a         benzothiophenylene group, a dibenzofuranylene group, a         dibenzothiophenylene group, a benzocarbazolylene group, a         dibenzocarbazolylene group, a dibenzosilolylene group, a         pyridinylene group, an imidazolylene group, a pyrazolylene         group, a thiazolylene group, an isothiazolylene group, an         oxazolylene group, an isoxazolylene group, a thiadiazolylene         group, an oxadiazolylene group, a pyrazinylene group, a         pyrimidinylene group, a pyridazinylene group, a triazinylene         group, a quinolinylene group, an isoquinolinylene group, a         benzoquinolinylene group, a phthalazinylene group, a         naphthyridinylene group, a quinoxalinylene group, a         quinazolinylene group, a cinnolinylene group, a         phenanthridinylene group, an acridinylene group, a         phenanthrolinylene group, a phenazinylene group, a         benzimidazolylene group, an isobenzothiazolylene group, a         benzoxazolylene group, an isobenzoxazolylene group, a         triazolylene group, a tetrazolylene group, an         imidazopyridinylene group, an imidazopyrimidinylene group, and         an azacarbazolylene group, each substituted with at least one         selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a         cyano group, a nitro group, an amidino group, a hydrazino group,         a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,         a phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl         group, a pyrimidinyl group, a pyridazinyl group, a triazinyl         group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, an isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group, an         azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),         —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),         and     -   Q₃₁ to Q₃a are the same as described herein above.

In one embodiment, R₃₀₁ to R₃₀₄ may each independently be selected from: a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and an azacarbazolyl group; and

-   -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl         group, a pyrimidinyl group, a pyridazinyl group, a triazinyl         group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, an isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group, and an         azacarbazolyl group, each substituted with at least one selected         from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amidino group, a hydrazino group, a         hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a         phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl         group, a pyrimidinyl group, a pyridazinyl group, a triazinyl         group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, an isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group, an         azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),         —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₂),         and     -   Q₃₁ to Q₃a are the same as described herein above.

In one embodiment, R₃₀₁ to R₃₀₄ in Formulae 301, 301-1, and 301-2 may each independently be selected from:

-   -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl         group, a pyrimidinyl group, a pyridazinyl group, a triazinyl         group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, an isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group, and an         azacarbazolyl group; and     -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl         group, a pyrimidinyl group, a pyridazinyl group, a triazinyl         group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, an isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group, and an         azacarbazolyl group, each substituted with at least one selected         from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amidino group, a hydrazino group, a         hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a         phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl         group, a pyrimidinyl group, a pyridazinyl group, a triazinyl         group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, an isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group, an         azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),         —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),         and     -   Q₃₁ to Q₃a are the same as described herein above.

In one embodiment, the first host may be represented by one selected from Formulae 301-1 to 301-6, and the second host may be represented by one selected from Formulae 301-7 to 301-9.

In one embodiment, the emission layer may include, as a host material, an alkaline earth metal complex. For example, the emission layer may include one selected from a Be complex (for example, Compound H55), a Mg complex, and a Zn complex.

In one embodiment, the first host and the second host may each independently include at least one selected from 9,10-di(2-naphthyl)anthracene (ADN), 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), 9,10-di-(2-naphthyl)-2-t-butyl-anthracene (TBADN), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di-9-carbazolylbenzene (mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), and Compounds H1 to H62, but embodiments of the present disclosure are not limited thereto:

In one or more embodiments, the first host may satisfy Equation 3-1:

S1(H1)−T1(H1)≤0.3 eV.  Equation 3-1

In Equation 3-1, S1(H1) is a singlet energy of the first host, and

T1(H1) is a triplet energy of the first host.

When the first host satisfies Equation 3-1, an energy difference ΔE_(st) between the triplet energy and the singlet energy of the first host is very low. Thus, reverse intersystem crossing from a triplet excited state to a singlet excited state through thermal activation is possible even at room temperature.

Accordingly, the exciton of the first host may transit (e.g., transition) from a triplet state to a singlet excited state and may be used for fluorescence, and may transit (e.g., transition) from the singlet excited state to the singlet excited state of the first dopant and may be used for light emission of the first dopant. Consequently, the fluorescence efficiency and lifespan characteristics of the organic light-emitting device may be improved.

In one embodiment, when the first host satisfies Equation 3-1, the first host may be a heterocyclic compound represented by Formula 11.

Dopant in Emission Layer

In one embodiment, the first dopant may be a fluorescent dopant or a delayed fluorescent dopant satisfying Equation 3-2:

S1(D1)−T1(D1)≤0.3 eV.  Equation 3-2

In Equation 3-2, S1(D1) is a singlet energy of the first dopant, and

T1(D1) is a triplet energy of the first dopant.

When the first dopant satisfies Equation 3-2, an energy difference ΔE_(st) between the triplet energy and the singlet energy of the first dopant is very low. Thus, reverse intersystem crossing from a triplet excited state to a singlet excited state through thermal activation is possible even at room temperature.

Accordingly, the exciton of the first dopant may transit (e.g., transition) from a triplet state to a singlet excited state and may be used for fluorescence. Consequently, the fluorescence efficiency and lifespan characteristics of the organic light-emitting device may be improved.

In one embodiment, an amount of the first host in the emission may be larger than an amount of the first dopant.

In one embodiment, a ratio of an emission component emitted from the first dopant to a total emission component emitted from the emission layer may be about 80% or more.

In one embodiment, the first dopant may be a heterocyclic compound represented by Formula 11:

(Ar₁)_(n1)—(L₁)_(m1)—(Ar₂)_(n2).  Formula 11

In Formula 1, L₁ may be a C₅-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group,

-   -   n1 and n2 may each independently be an integer from 0 to 3 and         may satisfy n1+n2≥1,     -   m1 may be an integer from 0 to 5, and     -   Ar₁ and Ar₂ may each independently be a group represented by         Formula 11A or 11B:

In Formulae 11A and 11B,

-   -   Y₁ and Y₂ may each independently be selected from a single bond,         —O—, —S—, —C(R_(10a))(R_(10b))—, —N(R_(10a))—,         Si(R_(10a))(R_(10b))—, —C(═O)—, —S(═O)₂—, —B(R_(10a))—,         —P(R_(10a))—, and —P(═O)(R_(10a))(R_(10b))—,     -   k1 and k2 may each independently be 0 or 1, and may satisfy         k1+k2≥1,     -   CY₁ and CY₂ may each independently be a C₅-C₆₀ carbocyclic group         or a C₁-C₆₀ heterocyclic group,     -   X₁ to X₃ may each independently be C or N,     -   when X₁ to X₃ are each C, at least one of R₃₀(s) may be a cyano         group,     -   R_(10a), R_(10b), R₁₀, R₂₀, and R₃₀ may each independently be         selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl         group, a cyano group, a nitro group, an amidino group, a         hydrazino group, a hydrazono group, a substituted or         unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted         C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀         alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy         group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a         substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a         substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or         unsubstituted C₆-C₆₀ aryloxy group, a substituted or         unsubstituted C₆-C₆₀ arylthio group, a substituted or         unsubstituted C₁-C₆₀ heteroaryl group, a substituted or         unsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or         unsubstituted C₁-C₆₀ heteroarylthio group, a substituted or         unsubstituted monovalent non-aromatic condensed polycyclic         group, a substituted or unsubstituted monovalent non-aromatic         condensed heteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂),         —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂),     -   a10 and a20 may each independently be an integer from 1 to 10,     -   a30 may be an integer from 1 to 6,     -   at least two of R_(10a), R_(10b), R₁₀, and R₂₀ may optionally be         linked to form a substituted or unsubstituted C₅-C₆₀ carbocyclic         group or a substituted or unsubstituted C₁-C₆₀ heterocyclic         group,     -   when a30 is 2 or more, two or more R₃₀(s) may optionally be         linked to form a substituted or unsubstituted C₅-C₆₀ carbocyclic         group or a substituted or unsubstituted C₁-C₆₀ heterocyclic         group,     -   at least one selected from R_(10a), R_(10b), R₁₀, and R₂₀ in         Formula 11A is a binding site to L₁ or Ar₁,     -   at least one of R₃₀(s) in Formula 11B is a binding site to L₁ or         Ar₁,     -   at least one substituent of the substituted C₅-C₆₀ carbocyclic         group, the substituted C₁-C₆₀ heterocyclic group, the         substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl         group, the substituted C₂-C₆₀ alkynyl group, the substituted         C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group,         the substituted C₁-C₁₀ heterocycloalkyl group, the substituted         C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀         heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the         substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀         arylthio group, the substituted C₁-C₆₀ heteroaryl group, the         substituted C₁-C₆₀ heteroaryloxy group, the substituted C₁-C₆₀         heteroarylthio group, the substituted monovalent non-aromatic         condensed polycyclic group, and the substituted monovalent         non-aromatic condensed heteropolycyclic group may be selected         from:     -   deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀         alkynyl group, and a C₁-C₆₀ alkoxy group;     -   a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, and a C₁-C₆₀ alkoxy group, each substituted with at least         one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,         a cyano group, a nitro group, an amidino group, a hydrazino         group, a hydrazono group, a C₃-C₁₀ cycloalkyl group, a C₁-C₆₀         heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₆₀         heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy         group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a         monovalent non-aromatic condensed polycyclic group, a monovalent         non-aromatic condensed heteropolycyclic group,         —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁),         —S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂);     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₆₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₆₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group;     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₆₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₆₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group, each substituted with at least         one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,         a cyano group, a nitro group, an amidino group, a hydrazino         group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl         group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀         cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀         cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀         aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a         C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed         polycyclic group, a monovalent non-aromatic condensed         heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂),         —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂);         and     -   —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),         —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and     -   Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each         independently be selected from hydrogen, deuterium, —F, —Cl,         —Br, —I, a hydroxyl group, a cyano group, a nitro group, an         amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀         alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a         C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₆₀         heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀         heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀         heteroaryl group, a monovalent non-aromatic condensed polycyclic         group, a monovalent non-aromatic condensed heteropolycyclic         group, a biphenyl group, and a terphenyl group.

In one embodiment, ring Ar₁ and ring Ar₂ in Formula 1 may each independently be a group represented by one selected from Formulae 11(1) to 11(4):

In Formulae 11(1) to 11(4),

-   -   Y₁₁ and Y₁₄ may each independently be selected from a single         bond, —O—, —S—, —C(R₁₅)(R₁₆)—, —N(R₁₅)—, Si(R₁₅)(R₁₆)—,         —C(═O)₂—, —S(═O)₂—, —B(R₁₅)—, —P(R₁₅)—, and —P(═O)(R₁₅)(R₁₆)—,     -   Y₁₅ may be N, B, or P,     -   ring CY₁₁ to ring CY₁₄ may each independently be selected from a         benzene group, a naphthalene group, a carbazole group, a         dibenzofuran group, a dibenzothiophene group, and a         dibenzosilole group,     -   R₁ to R₁₆ may each independently be selected from a binding site         to L₁ or Ar₁, hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl         group, a cyano group, a nitro group, an amidino group, a         hydrazino group, a hydrazono group, a substituted or         unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted         C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀         alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy         group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a         substituted or unsubstituted C₃-C₁ cycloalkenyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a         substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or         unsubstituted C₆-C₆₀ aryloxy group, a substituted or         unsubstituted C₆-C₆₀ arylthio group, a substituted or         unsubstituted C₁-C₆₀ heteroaryl group, a substituted or         unsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or         unsubstituted C₁-C₆₀ heteroarylthio group, a substituted or         unsubstituted monovalent non-aromatic condensed polycyclic         group, a substituted or unsubstituted monovalent non-aromatic         condensed heteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂),         —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂),     -   at least two substituents selected from R₁₁ to R₁₆ may         optionally be linked to form a substituted or unsubstituted         C₅-C₆₀ carbocyclic group or a substituted or unsubstituted         C₁-C₆₀ heterocyclic group,     -   at least one selected from R₁₁ to R₁₆ may be a binding site to         L₁ or Ar₁,     -   a11 to a14 may each independently be an integer from 1 to 6, and     -   Q₁ to Q₃ may each independently be selected from hydrogen,         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀         alkynyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl         group, a terphenyl group, a fluorenyl group, a spiro-bifluorenyl         group, a benzofluorenyl group, a dibenzofluorenyl group, a         phenalenyl group, a phenanthrenyl group, an anthracenyl group, a         fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a         pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a         quinolinyl group, an isoquinolinyl group, a benzoquinolinyl         group, a naphthyridinyl group, a quinoxalinyl group, a         quinazolinyl group, a carbazolyl group, a phenanthridinyl group,         an acridinyl group, a phenanthrolinyl group, a phenazinyl group,         a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl         group, a biphenyl group, and a terphenyl group.

In one embodiment, L₁ in Formula 1 may be selected from a single bond, a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-Cia cycloalkenylene group, a substituted or unsubstituted C₁-C₆₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group.

In one embodiment, L₁ may be selected from:

-   -   a phenylene group, a naphthylene group, a fluorenylene group, a         spiro-bifluorenylene group, a benzofluorenylene group, a         dibenzofluorenylene group, a phenanthrenylene group, an         anthracenylene group, a fluoranthenylene group, a         triphenylenylene group, a pyrenylene group, a chrysenylene         group, a perylenylene group, a pentaphenylene group, a         hexacenylene group, a pentacenylene group, a thiophenylene         group, a furanylene group, a carbazolylene group, an indolylene         group, an isoindolylene group, a benzofuranylene group, a         benzothiophenylene group, a dibenzofuranylene group, a         dibenzothiophenylene group, a benzocarbazolylene group, a         dibenzocarbazolylene group, a dibenzosilolylene group, a         pyridinylene group, an imidazolylene group, a pyrazolylene         group, a thiazolylene group, an isothiazolylene group, an         oxazolylene group, an isoxazolylene group, a thiadiazolylene         group, an oxadiazolylene group, a pyrazinylene group, a         pyrimidinylene group, a pyridazinylene group, a triazinylene         group, a quinolinylene group, an isoquinolinylene group, a         benzoquinolinylene group, a phthalazinylene group, a         naphthyridinylene group, a quinoxalinylene group, a         quinazolinylene group, a cinnolinylene group, a         phenanthridinylene group, an acridinylene group, a         phenanthrolinylene group, a phenazinylene group, a         benzimidazolylene group, an isobenzothiazolylene group, a         benzoxazolylene group, an isobenzoxazolylene group, a         triazolylene group, a tetrazolylene group, an         imidazopyridinylene group, an imidazopyrimidinylene group, and         an azacarbazolylene group; and     -   a phenylene group, a naphthylene group, a fluorenylene group, a         spiro-bifluorenylene group, a benzofluorenylene group, a         dibenzofluorenylene group, a phenanthrenylene group, an         anthracenylene group, a fluoranthenylene group, a         triphenylenylene group, a pyrenylene group, a chrysenylene         group, a perylenylene group, a pentaphenylene group, a         hexacenylene group, a pentacenylene group, a thiophenylene         group, a furanylene group, a carbazolylene group, an indolylene         group, an isoindolylene group, a benzofuranylene group, a         benzothiophenylene group, a dibenzofuranylene group, a         dibenzothiophenylene group, a benzocarbazolylene group, a         dibenzocarbazolylene group, a dibenzosilolylene group, a         pyridinylene group, an imidazolylene group, a pyrazolylene         group, a thiazolylene group, an isothiazolylene group, an         oxazolylene group, an isoxazolylene group, a thiadiazolylene         group, an oxadiazolylene group, a pyrazinylene group, a         pyrimidinylene group, a pyridazinylene group, a triazinylene         group, a quinolinylene group, an isoquinolinylene group, a         benzoquinolinylene group, a phthalazinylene group, a         naphthyridinylene group, a quinoxalinylene group, a         quinazolinylene group, a cinnolinylene group, a         phenanthridinylene group, an acridinylene group, a         phenanthrolinylene group, a phenazinylene group, a         benzimidazolylene group, an isobenzothiazolylene group, a         benzoxazolylene group, an isobenzoxazolylene group, a         triazolylene group, a tetrazolylene group, an         imidazopyridinylene group, an imidazopyrimidinylene group, and         an azacarbazolylene group, each substituted with at least one         selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a         cyano group, a nitro group, an amidino group, a hydrazino group,         a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,         a phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl         group, a pyrimidinyl group, a pyridazinyl group, a triazinyl         group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, an isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group, an         azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),         —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),         and     -   Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀         alkyl group, a C₁-C₁ alkoxy group, a phenyl group, a phenyl         group substituted with a C₁-C₁₀ alkyl group, a biphenyl group, a         terphenyl group, and a naphthyl group.

In one embodiment, L₁ may be a single bond or a group represented by one selected from Formulae 3-1 to 3-35:

In Formulae 3-1 to 3-35, X₁₁ may be *—O—*′, *—S—*′, or *—N(Z₁₅)—*′,

-   -   Z₁ to Z₄, Z₁₁, Z₁₂, and Z₁₅ may each independently be selected         from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a         C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a         terphenyl group, a naphthyl group, a fluorenyl group, a         spiro-bifluorenyl group, a benzofluorenyl group, a         dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl         group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a         pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a         quinolinyl group, an isoquinolinyl group, a quinoxalinyl group,         a quinazolinyl group, a carbazolyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a triazinyl group, a         benzimidazolyl group, a phenanthrolinyl group, and         —Si(Q₃₁)(Q₃₂)(Q₃₃),     -   Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀         alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl         group, a terphenyl group, and a naphthyl group,     -   d2 may be an integer from 0 to 2,     -   d3 may be an integer from 0 to 3,     -   d4 may be an integer from 0 to 4,     -   d5 may be an integer from 0 to 5,     -   d6 may be an integer from 0 to 6,     -   d8 may be an integer from 0 to 8, and     -   * and *′ indicate a binding site to a neighboring atom.

In one embodiment, at least one selected from Ar₁ and Ar₂ in Formula 1 may be a group represented by one selected from Formulae 4-1 to 4-36:

In Formulae 4-1 to 4-36, Y₂₁ and Y₂₂ may each independently be O, S, C(Z₂₆)(Z₂₇), N(Z₂₆), or Si(Z₂₆)(Z₂₇),

-   -   Y₂₃ to Y₂₆ may each independently be single bond, O, S,         C(Z₂₈)(Z₂₉), N(Z₂₈), or Si(Z₂₈)(Z₂₉),     -   Y₂ may be N, B, or P,     -   Z₂₁ to Z₂₈ may each independently be selected from hydrogen,         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amino group, an amidino group, a hydrazino         group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy         group, a phenyl group, a biphenyl group, a terphenyl group, a         naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a pyrenyl group, a chrysenyl group,         a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a         pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a         quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a         dibenzofuranyl group, a dibenzothiophenyl group, a triazinyl         group, a benzimidazolyl group, a phenanthrolinyl group, and         —Si(Q₃₁)(Q₃₂)(Q₃₃),     -   Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀         alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl         group, a terphenyl group, and a naphthyl group,     -   g2 may be 1 or 2,     -   g3 may be an integer from 1 to 3,     -   g4 may be an integer from 1 to 4,     -   g5 may be an integer from 1 to 5,     -   g7 may be an integer from 1 to 7,     -   g8 may be an integer from 1 to 8, and     -   * indicates a binding site to a neighboring atom.

In one embodiment, R_(10a), R_(10b), R₁₀, R₂₀, and R₃₀ may each independently be selected from:

-   -   hydrogen, deuterium, —F, —Cl, —Br, —I, a methyl group, an ethyl         group, an n-propyl group, an isopropyl group, an n-butyl group,         a sec-butyl group, an isobutyl group, a tert-butyl group, an         ethenyl group, a propenyl group, a butenyl group, a methoxy         group, an ethoxy group, an n-propoxy group, an isopropoxy group,         an n-butoxy group, a sec-butoxy group, an isobutoxy group, and         tert-butoxy group;     -   a methyl group, an ethyl group, an n-propyl group, an isopropyl         group, an n-butyl group, a sec-butyl group, an isobutyl group, a         tert-butyl group, a methoxy group, an ethoxy group, an n-propoxy         group, an isopropoxy group, an n-butoxy group, a sec-butoxy         group, an isobutoxy group, and a tert-butoxy group, each         substituted with at least one selected from deuterium, —F, —Cl,         —Br, —I, a cyano group, a phenyl group, and a biphenyl group;     -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclopentenyl group, a cyclohexenyl group, a phenyl group, a         biphenyl group, a terphenyl group, a pentalenyl group, an         indenyl group, a naphthyl group, an azulenyl group, an indacenyl         group, an acenaphthyl group, a fluorenyl group, a         spiro-bifluorenyl group, a benzofluorenyl group, a         dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentacenyl group, a pyrrolyl group, a         thiophenyl group, a furanyl group, a silolyl group, an         imidazolyl group, a pyrazolyl group, a thiazolyl group, an         isothiazolyl group, an oxazolyl group, an isoxazolyl group, a         pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a         pyridazinyl group, an indolyl group, an isoindolyl group, an         indazolyl group, a purinyl group, a quinolinyl group, an         isoquinolinyl group, a benzoquinolinyl group, a         benzoisoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a benzoquinoxalinyl group, a         quinazolinyl group, a benzoquinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, a benzofuranyl group, a benzothiophenyl group, a         benzosilolyl group, a benzothiazolyl group, a benzoisothiazolyl         group, a benzoxazolyl group, a benzoisoxazolyl group, a         triazolyl group, a tetrazolyl group, a thiadiazolyl group, an         oxadiazolyl group, a triazinyl group, a carbazolyl group, a         dibenzofuranyl group, a dibenzothiophenyl group, a         dibenzosilolyl group, a benzocarbazolyl group, a         naphthobenzofuranyl group, a naphthobenzothiophenyl group, a         naphthobenzosilolyl group, a dibenzocarbazolyl group, a         dinaphthofuranyl group, a dinaphthothiophenyl group, a dinaphtho         silolyl group, an imidazopyridinyl group, an imidazopyrimidinyl         group, an oxazolopyridinyl group, a thiazolopyridinyl group, a         benzonaphthyridinyl group, an azafluorenyl group, an         azaspiro-bifluorenyl group, an azacarbazolyl group, an         azadibenzofuranyl group, an azadibenzothiophenyl group, an         azadibenzosilolyl group, an indenopyrrolyl group, an         indolopyrrolyl group, an indeno carbazolyl group, and an         indolocarbazolyl group;     -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclopentenyl group, a cyclohexenyl group, a phenyl group, a         biphenyl group, a terphenyl group, a pentalenyl group, an         indenyl group, a naphthyl group, an azulenyl group, an indacenyl         group, an acenaphthyl group, a fluorenyl group, a         spiro-bifluorenyl group, a benzofluorenyl group, a         dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentacenyl group, a pyrrolyl group, a         thiophenyl group, a furanyl group, a silolyl group, an         imidazolyl group, a pyrazolyl group, a thiazolyl group, an         isothiazolyl group, an oxazolyl group, an isoxazolyl group, a         pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a         pyridazinyl group, an indolyl group, an isoindolyl group, an         indazolyl group, a purinyl group, a quinolinyl group, an         isoquinolinyl group, a benzoquinolinyl group, a         benzoisoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a benzoquinoxalinyl group, a         quinazolinyl group, a benzoquinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, a benzofuranyl group, a benzothiophenyl group, a         benzosilolyl group, a benzothiazolyl group, a benzoisothiazolyl         group, a benzoxazolyl group, a benzoisoxazolyl group, a         triazolyl group, a tetrazolyl group, a thiadiazolyl group, an         oxadiazolyl group, a triazinyl group, a carbazolyl group, a         dibenzofuranyl group, a dibenzothiophenyl group, a         dibenzosilolyl group, a benzocarbazolyl group, a         naphthobenzofuranyl group, a naphthobenzothiophenyl group, a         naphthobenzosilolyl group, a dibenzocarbazolyl group, a         dinaphthofuranyl group, a dinaphthothiophenyl group, a dinaphtho         silolyl group, an imidazopyridinyl group, an imidazopyrimidinyl         group, an oxazolopyridinyl group, a thiazolopyridinyl group, a         benzonaphthyridinyl group, an azafluorenyl group, an         azaspiro-bifluorenyl group, an azacarbazolyl group, an         azadibenzofuranyl group, an azadibenzothiophenyl group, an         azadibenzosilolyl group, an indenopyrrolyl group, an         indolopyrrolyl group, an indeno carbazolyl group, and an         indolocarbazolyl group, each substituted with at least one         selected from deuterium, —F, —Cl, —Br, —I, a cyano group, a         methyl group, an ethyl group, an n-propyl group, an isopropyl         group, an n-butyl group, a sec-butyl group, an isobutyl group, a         tert-butyl group, a methoxy group, an ethoxy group, an n-propoxy         group, an isopropoxy group, an n-butoxy group, a sec-butoxy         group, an isobutoxy group, tert-butoxy group, a cyclopentyl         group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl         group, a cyclohexenyl group, a phenyl group, a biphenyl group, a         terphenyl group, a pentalenyl group, an indenyl group, a         naphthyl group, an azulenyl group, an indacenyl group, an         acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group,         a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl         group, a phenanthrenyl group, an anthracenyl group, a         fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a         chrysenyl group, a perylenyl group, a pentacenyl group, a         pyrrolyl group, a thiophenyl group, a furanyl group, a silolyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl         group, a pyridazinyl group, an indolyl group, an isoindolyl         group, an indazolyl group, a purinyl group, a quinolinyl group,         an isoquinolinyl group, a benzoquinolinyl group, a         benzoisoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a benzoquinoxalinyl group, a         quinazolinyl group, a benzoquinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, a benzofuranyl group, a benzothiophenyl group, a         benzosilolyl group, a benzothiazolyl group, a benzoisothiazolyl         group, a benzoxazolyl group, a benzoisoxazolyl group, a         triazolyl group, a tetrazolyl group, a thiadiazolyl group, an         oxadiazolyl group, a triazinyl group, a carbazolyl group, a         dibenzofuranyl group, a dibenzothiophenyl group, a         dibenzosilolyl group, a benzocarbazolyl group, a         naphthobenzofuranyl group, a naphthobenzothiophenyl group, a         naphthobenzosilolyl group, a dibenzocarbazolyl group, a         dinaphthofuranyl group, a dinaphthothiophenyl group, a dinaphtho         silolyl group, an imidazopyridinyl group, an imidazopyrimidinyl         group, an oxazolopyridinyl group, a thiazolopyridinyl group, a         benzonaphthyridinyl group, an azafluorenyl group, an         azaspiro-bifluorenyl group, an azacarbazolyl group, an         azadibenzofuranyl group, an azadibenzothiophenyl group, an         azadibenzosilolyl group, an indenopyrrolyl group, an         indolopyrrolyl group, an indeno carbazolyl group, an         indolocarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),         —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)(Q₃₁), —S(═O)₂(Q₃₁),         —P(═O)(Q₃₁)(Q₃₂), and —P(═S)(Q₃₁)(Q₃₂); and     -   —N(Q₁₁)(Q₁₂).

In one embodiment, R_(10a), R_(10b), R₁₀, R₂₀, and R₃₀ may each independently be selected from:

-   -   hydrogen, deuterium, —F, —Cl, —Br, —I, a methyl group, an ethyl         group, an n-propyl group, an isopropyl group, an n-butyl group,         a sec-butyl group, an isobutyl group, a tert-butyl group, an         ethenyl group, a propenyl group, a butenyl group, a methoxy         group, an ethoxy group, an n-propoxy group, an isopropoxy group,         an n-butoxy group, a sec-butoxy group, an isobutoxy group, and a         tert-butoxy group; and     -   a group represented by one selected from Formulae 5-1 to 5-26         and 6-1 to 6-55:

In Formulae 5-1 to 5-26 and 6-1 to 6-55,

-   -   Y₃₁ and Y₃₂ may each independently be O, S, C(Z₃₃)(Z₃₄), N(Z₃₃),         or     -   Z₃₁ to Z₃₄ may each independently be selected from hydrogen,         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkenyl group, a C₁-C₂₀         alkynyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl         group, a terphenyl group, a naphthyl group, a fluorenyl group, a         spiro-bifluorenyl group, a phenanthrenyl group, an anthracenyl         group, a triphenylenyl group, a pyridinyl group, a pyrimidinyl         group, a carbazolyl group, and a triazinyl group,     -   e2 may be 1 or 2,     -   e3 may be an integer from 1 to 3,     -   e4 may be an integer from 1 to 4,     -   e5 may be an integer from 1 to 5,     -   e6 may be an integer from 1 to 6,     -   e7 may be an integer from 1 to 7,     -   e9 may be an integer from 1 to 9, and     -   * indicates a binding site to a neighboring atom.

In one embodiment, the first dopant may be selected from Compounds 12-1 to 12-12:

In the heterocyclic compound represented by Formula 11, because Ar₁ and Ar₂ have the above-described structure, substituents having properties of an electron withdrawing group (EWG) and an electron donating group (EDG) may be included in the compound. By introducing these substituents at suitable or appropriate positions, an energy difference between a singlet state and a triplet state of the compound may be suitably or appropriately adjusted. Therefore, the heterocyclic compound may exhibit thermally activated delayed fluorescence (TADF).

The singlet energy (S1) and the triplet energy (T1) in the heterocyclic compound satisfy the following Equation:

ΔE _(st) =|T1−S1|≤0.3 eV.

In some embodiments, the heterocyclic compound separates the electron donating moiety from the electron accepting moiety, thereby effectively preventing or reducing intramolecular orbital overlap. Therefore, singlet and triplet of the molecule do not overlap each other, and thus, ΔE_(st) may be very low. Therefore, reverse intersystem crossing from a triplet excited state to a singlet excited state through thermal activation is possible even at room temperature. Therefore, the heterocyclic compound may exhibit thermally activated delayed fluorescence (TADF). In this manner, an exciton in a triplet state is used for light emission, thereby improving luminescence efficiency.

Furthermore, because the heterocyclic compound has relatively high charge (hole or electron) transport capability, an exciton formation proportion in an emission layer in an organic light-emitting device including the heterocyclic compound represented by Formula 11 may be improved. Therefore, the organic light-emitting device may have a low driving voltage, high efficiency, a long lifespan, and high maximum quantum efficiency.

In one embodiment, the first dopant may be a fluorescent dopant, and the fluorescent dopant may include an arylamine compound or a styrylamine compound.

In addition, the fluorescent dopant may include a compound represented by Formula 501:

In Formula 501, Ar₅₀₁ may be a substituted or unsubstituted C₅-C₆₀

-   -   carbocyclic group or a substituted or unsubstituted C₁-C₆₀         heterocyclic group,     -   L₅₀₁ to L₅₀₃ may each independently be selected from a         substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a         substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group,         a substituted or unsubstituted C₆-C₆₀ arylene group, a         substituted or unsubstituted C₁-C₆₀ heteroarylene group, a         substituted or unsubstituted divalent non-aromatic condensed         polycyclic group, and a substituted or unsubstituted divalent         non-aromatic condensed heteropolycyclic group,     -   xd1 to xd3 may each independently be an integer from 0 to 3,     -   R₅₀₁ and R₅₀₂ may each independently be selected from a         substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a         substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a         substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or         unsubstituted C₆-C₆₀ aryloxy group, a substituted or         unsubstituted C₆-C₆₀ arylthio group, a substituted or         unsubstituted C₁-C₆₀ heteroaryl group, a substituted or         unsubstituted monovalent non-aromatic condensed polycyclic         group, and a substituted or unsubstituted monovalent         non-aromatic condensed heteropolycyclic group, and     -   xd4 may be an integer from 1 to 6.

In one embodiment, Ar₅₀₁ in Formula 501 may be selected from:

-   -   a naphthalene group, a heptalene group, a fluorene group, a         spiro-bifluorene group, a benzofluorene group, a dibenzofluorene         group, a phenalene group, a phenanthrene group, an anthracene         group, a fluoranthene group, a triphenylene group, a pyrene         group, a chrysene group, a naphthacene group, a picene group, a         perylene group, a pentaphene group, an indenoanthracene group,         indeno phenanthrene group, and

-   -    and     -   a naphthalene group, a heptalene group, a fluorene group, a         spiro-bifluorene group, a benzofluorene group, a dibenzofluorene         group, a phenalene group, a phenanthrene group, an anthracene         group, a fluoranthene group, a triphenylene group, a pyrene         group, a chrysene group, a naphthacene group, a picene group, a         perylene group, a pentaphene group, an indenoanthracene group,         an indeno phenanthrene group, and

-   -    each substituted with at least one selected from deuterium, —F,         —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an         amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀         alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl         group, a terphenyl group, and a naphthyl group.

In one or more embodiments, L₅₀₁ to L₅₀₃ in Formula 501 may each independently be selected from:

-   -   a phenylene group, a naphthylene group, a fluorenylene group, a         spiro-bifluorenylene group, a benzofluorenylene group, a         dibenzofluorenylene group, a phenanthrenylene group, an         anthracenylene group, a fluoranthenylene group, a         triphenylenylene group, a pyrenylene group, a chrysenylene         group, a perylenylene group, a pentaphenylene group, a         hexacenylene group, a pentacenylene group, a thiophenylene         group, a furanylene group, a carbazolylene group, an indolylene         group, an isoindolylene group, a benzofuranylene group, a         benzothiophenylene group, a dibenzofuranylene group, a         dibenzothiophenylene group, a benzocarbazolylene group, a         dibenzocarbazolylene group, a dibenzosilolylene group, and a         pyridinylene group; and     -   a phenylene group, a naphthylene group, a fluorenylene group, a         spiro-bifluorenylene group, a benzofluorenylene group, a         dibenzofluorenylene group, a phenanthrenylene group, an         anthracenylene group, a fluoranthenylene group, a         triphenylenylene group, a pyrenylene group, a chrysenylene         group, a perylenylene group, a pentaphenylene group, a         hexacenylene group, a pentacenylene group, a thiophenylene         group, a furanylene group, a carbazolylene group, an indolylene         group, an isoindolylene group, a benzofuranylene group, a         benzothiophenylene group, a dibenzofuranylene group, a         dibenzothiophenylene group, a benzocarbazolylene group, a         dibenzocarbazolylene group, a dibenzosilolylene group, and a         pyridinylene group, each substituted with at least one selected         from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amidino group, a hydrazino group, a         hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a         phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl         group.

In one or more embodiments, R₅₀₁ and R₅₀₂ in Formula 501 may each independently be selected from:

-   -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl         group; and     -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl         group, each substituted with at least one selected from         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl         group, a biphenyl group, a terphenyl group, a naphthyl group, a         fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl         group, a dibenzofluorenyl group, a phenanthrenyl group, an         anthracenyl group, a fluoranthenyl group, a triphenylenyl group,         a pyrenyl group, a chrysenyl group, a perylenyl group, a         pentaphenyl group, a hexacenyl group, a pentacenyl group, a         thiophenyl group, a furanyl group, a carbazolyl group, an         indolyl group, an isoindolyl group, a benzofuranyl group, a         benzothiophenyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, and —Si(Q₃₁)(Q₃₂)(Q₃₃), and     -   Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀         alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl         group, a terphenyl group, and a naphthyl group.

In one or more embodiments, xd4 in Formula 501 may be 2, but embodiments of the present disclosure are not limited thereto.

For example, the fluorescent dopant may be selected from Compounds FD1 to FD23:

In one or more embodiment, the fluorescent dopant may be selected from the following compounds, but embodiments of the present disclosure are not limited thereto.

In one embodiment, the emission layer may further include a second dopant, and the second dopant may be a fluorescent dopant or a delayed fluorescent dopant satisfying Equation 3-3:

S1(D2)−T1(D2)≤0.3 eV.  Equation 3-3

In Equation 3-3, S1(D2) is a singlet energy of the second dopant, and

T1(D2) is a triplet energy of the second dopant.

In one embodiment, the second dopant may be selected from a heterocyclic compound represented by Formula 11 or a fluorescent dopant.

Electron Transport Region in Organic Layer 150

The electron transport region may have i) a single-layered structure including a single layer including a single material, ii) a single-layered structure including a single layer including a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including a plurality of different materials.

The electron transport region may include at least one selected from a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, and an electron injection layer, but embodiments of the present disclosure are not limited thereto.

For example, the electron transport region may have an electron transport layer/electron injection layer structure, a hole blocking layer/electron transport layer/electron injection layer structure, an electron control layer/electron transport layer/electron injection layer structure, or a buffer layer/electron transport layer/electron injection layer structure, wherein for each structure, constituting layers are sequentially stacked from an emission layer. However, embodiments of the structure of the electron transport region are not limited thereto.

The electron transport region (for example, a buffer layer, a hole blocking layer, an electron control layer, or an electron transport layer in the electron transport region) may include a metal-free compound containing at least one Tr electron-depleted nitrogen-containing ring.

The term “π electron-depleted nitrogen-containing ring,” as used herein, indicates a C₁-C₆₀ heterocyclic group having at least one *—N═* moiety as a ring-forming moiety.

For example, the “π electron-depleted nitrogen-containing ring” may be i) a 5-membered to 7-membered heteromonocyclic group having at least one *—N═* moiety, ii) a heteropolycyclic group in which two or more 5-membered to 7-membered heteromonocyclic groups each having at least one *—N═*′ moiety are condensed with each other, or iii) a heteropolycyclic group in which at least one of 5-membered to 7-membered heteromonocyclic groups, each having at least one *—N═*′ moiety, is condensed with at least one C₅-C₆₀ carbocyclic group.

Examples of the Tr electron-depleted nitrogen-containing ring include an imidazole, a pyrazole, a thiazole, an isothiazole, an oxazole, an isoxazole, a pyridine, a pyrazine, a pyrimidine, a pyridazine, an indazole, a purine, a quinoline, an isoquinoline, a benzoquinoline, a phthalazine, a naphthyridine, a quinoxaline, a quinazoline, a cinnoline, a phenanthridine, an acridine, a phenanthroline, a phenazine, a benzimidazole, an isobenzothiazole, a benzoxazole, an isobenzoxazole, a triazole, a tetrazole, an oxadiazole, a triazine, a thiadiazole, an imidazopyridine, an imidazopyrmidine, and an azacarbazole, but are not limited thereto.

For example, the electron transport region may include a compound represented by Formula 601:

[Ar₆₀₁]_(xe11)—[(L₆₀₁)_(xe1)—R₆₀₁]_(xe21).  Formula 601

In Formula 601,

-   -   Ar₆₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic         group or a substituted or unsubstituted C₁-C₆₀ heterocyclic         group,     -   xe11 may be 1, 2, or 3,     -   L₆₀₁ may each independently be selected from a substituted or         unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or         unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or         unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or         unsubstituted C₁-C₆₀ heterocycloalkenylene group, a substituted         or unsubstituted C₆-C₆₀ arylene group, a substituted or         unsubstituted C₁-C₆₀ heteroarylene group, a substituted or         unsubstituted divalent non-aromatic condensed polycyclic group,         and a substituted or unsubstituted divalent non-aromatic         condensed heteropolycyclic group;     -   xe1 may be an integer from 0 to 5,     -   R₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀         cycloalkyl group, a substituted or unsubstituted C₁-C₁₀         heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀         cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀         heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀         aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group,         a substituted or unsubstituted C₆-C₆₀ arylthio group, a         substituted or unsubstituted C₁-C₆₀ heteroaryl group, a         substituted or unsubstituted monovalent non-aromatic condensed         polycyclic group, a substituted or unsubstituted monovalent         non-aromatic condensed heteropolycyclic group,         —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁), —S(═O)₂(Q₆₀₁), and         —P(═O)(Q₆₀₁)(Q₆₀₂),     -   Q₆₀₁ to Q₆₀₃ may each independently be a C₁-C₁₀ alkyl group, a         C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a         terphenyl group, or a naphthyl group, and     -   xe21 may be an integer from 1 to 5.

In one embodiment, at least one of Ar₆₀₁(s) in the number of xe11 and R₆₀₁(s) in the number of xe21 may include the Tr electron-depleted nitrogen-containing ring.

In one embodiment, Ar₆₀₁ in Formula 601 may be selected from:

-   -   a benzene group, a naphthalene group, a fluorene group, a         spiro-bifluorene group, a benzofluorene group, a dibenzofluorene         group, a phenalene group, a phenanthrene group, an anthracene         group, a fluoranthene group, a triphenylene group, a pyrene         group, a chrysene group, a naphthacene group, a picene group, a         perylene group, a pentaphene group, an indenoanthracene group, a         dibenzofuran group, a dibenzothiophene group, a carbazole group,         an imidazole group, a pyrazole group, a thiazole group, an         isothiazole group, an oxazole group, an isoxazole group, a         pyridine group, a pyrazine group, a pyrimidine group, a         pyridazine group, an indazole group, a purine group, a quinoline         group, an isoquinoline group, a benzoquinoline group, a         phthalazine group, a naphthyridine group, a quinoxaline group, a         quinazoline group, a cinnoline group, a phenanthridine group, an         acridine group, a phenanthroline group, a phenazine group, a         benzimidazole group, an isobenzothiazole group, a benzoxazole         group, an isobenzoxazole group, a triazole group, a tetrazole         group, an oxadiazole group, a triazine group, a thiadiazole         group, an imidazopyridine group, an imidazopyrmidine group, and         an azacarbazole group; and     -   a benzene group, a naphthalene group, a fluorene group, a         spiro-bifluorene group, a benzofluorene group, a dibenzofluorene         group, a phenalene group, a phenanthrene group, an anthracene         group, a fluoranthene group, a triphenylene group, a pyrene         group, a chrysene group, a naphthacene group, a picene group, a         perylene group, a pentaphene group, an indenoanthracene group, a         dibenzofuran group, a dibenzothiophene group, a carbazole group,         an imidazole group, a pyrazole group, a thiazole group, an         isothiazole group, an oxazole group, an isoxazole group, a         pyridine group, a pyrazine group, a pyrimidine group, a         pyridazine group, an indazole group, a purine group, a quinoline         group, an isoquinoline group, a benzoquinoline group, a         phthalazine group, a naphthyridine group, a quinoxaline group, a         quinazoline group, a cinnoline group, a phenanthridine group, an         acridine group, a phenanthroline group, a phenazine group, a         benzimidazole group, an isobenzothiazole group, a benzoxazole         group, an isobenzoxazole group, a triazole group, a tetrazole         group, an oxadiazole group, a triazine group, a thiadiazole         group, an imidazopyridine group, an imidazopyrimidine group, and         an azacarbazole group, each substituted with at least one         selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a         cyano group, a nitro group, an amidino group, a hydrazino group,         a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,         a phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),         and     -   Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀         alkyl group, a C₁-C₁ alkoxy group, a phenyl group, a biphenyl         group, a terphenyl group, and a naphthyl group.

When xe11 in Formula 601 is 2 or more, two or more Ar₆₀₁(s) may be linked via a single bond.

In one or more embodiments, Ar₆₀₁ in Formula 601 may be an anthracene group.

In one or more embodiments, a compound represented by Formula 601 may be represented by Formula 601-1:

In Formula 601-1, X₆₁₄ may be N or C(R₆₁₄), X₆₁₅ may be N or C(R₆₁₅), X₆₁₆ may be N or C(R₆₁₆), and at least one selected from X₆₁₄ to X₆₁₆ may be N,

-   -   L₆₁₁ to L₆₁₃ may each independently be the same as described in         connection with L₆₀₁,     -   xe611 to xe613 may each independently be the same as described         in connection with xe1,     -   R₆₁₁ to R₆₁₃ may each independently be the same as described in         connection with R₆₀₁, and     -   R₆₁₄ to R₆₁₆ may each independently be selected from hydrogen,         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl         group, a biphenyl group, a terphenyl group, and a naphthyl         group.

In one embodiment, L₆₀₁ and L₆₁₁ to L₆₁₃ in Formulae 601 and 601-1 may each independently be selected from:

-   -   a phenylene group, a naphthylene group, a fluorenylene group, a         spiro-bifluorenylene group, a benzofluorenylene group, a         dibenzofluorenylene group, a phenanthrenylene group, an         anthracenylene group, a fluoranthenylene group, a         triphenylenylene group, a pyrenylene group, a chrysenylene         group, a perylenylene group, a pentaphenylene group, a         hexacenylene group, a pentacenylene group, a thiophenylene         group, a furanylene group, a carbazolylene group, an indolylene         group, an isoindolylene group, a benzofuranylene group, a         benzothiophenylene group, a dibenzofuranylene group, a         dibenzothiophenylene group, a benzocarbazolylene group, a         dibenzocarbazolylene group, a dibenzosilolylene group, a         pyridinylene group, an imidazolylene group, a pyrazolylene         group, a thiazolylene group, an isothiazolylene group, an         oxazolylene group, an isoxazolylene group, a thiadiazolylene         group, an oxadiazolylene group, a pyrazinylene group, a         pyrimidinylene group, a pyridazinylene group, a triazinylene         group, a quinolinylene group, an isoquinolinylene group, a         benzoquinolinylene group, a phthalazinylene group, a         naphthyridinylene group, a quinoxalinylene group, a         quinazolinylene group, a cinnolinylene group, a         phenanthridinylene group, an acridinylene group, a         phenanthrolinylene group, a phenazinylene group, a         benzimidazolylene group, an isobenzothiazolylene group, a         benzoxazolylene group, an isobenzoxazolylene group, a         triazolylene group, a tetrazolylene group, an         imidazopyridinylene group, an imidazopyrimidinylene group, and         an azacarbazolylene group; and     -   a phenylene group, a naphthylene group, a fluorenylene group, a         spiro-bifluorenylene group, a benzofluorenylene group, a         dibenzofluorenylene group, a phenanthrenylene group, an         anthracenylene group, a fluoranthenylene group, a         triphenylenylene group, a pyrenylene group, a chrysenylene         group, a perylenylene group, a pentaphenylene group, a         hexacenylene group, a pentacenylene group, a thiophenylene         group, a furanylene group, a carbazolylene group, an indolylene         group, an isoindolylene group, a benzofuranylene group, a         benzothiophenylene group, a dibenzofuranylene group, a         dibenzothiophenylene group, a benzocarbazolylene group, a         dibenzocarbazolylene group, a dibenzosilolylene group, a         pyridinylene group, an imidazolylene group, a pyrazolylene         group, a thiazolylene group, an isothiazolylene group, an         oxazolylene group, an isoxazolylene group, a thiadiazolylene         group, an oxadiazolylene group, a pyrazinylene group, a         pyrimidinylene group, a pyridazinylene group, a triazinylene         group, a quinolinylene group, an isoquinolinylene group, a         benzoquinolinylene group, a phthalazinylene group, a         naphthyridinylene group, a quinoxalinylene group, a         quinazolinylene group, a cinnolinylene group, a         phenanthridinylene group, an acridinylene group, a         phenanthrolinylene group, a phenazinylene group, a         benzimidazolylene group, an isobenzothiazolylene group, a         benzoxazolylene group, an isobenzoxazolylene group, a         triazolylene group, a tetrazolylene group, an         imidazopyridinylene group, an imidazopyrimidinylene group, and         an azacarbazolylene group, each substituted with at least one         selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a         cyano group, a nitro group, an amidino group, a hydrazino group,         a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,         a phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl         group, a pyrimidinyl group, a pyridazinyl group, a triazinyl         group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, an isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a trazolyl group, a tetrazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group, and an         azacarbazolyl group,     -   but embodiments of the present disclosure are not limited         thereto.

In one or more embodiments, xe1 and xe611 to xe613 in Formulae 601 and 601-1 may each independently be 0, 1, or 2.

In one or more embodiments, Reo, and R₆₁₁ to R₆₁₃ in Formula 601 and 601-1 may each independently be selected from:

-   -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl         group, a pyrimidinyl group, a pyridazinyl group, a triazinyl         group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, an isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group, and an         azacarbazolyl group;     -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl         group, a pyrimidinyl group, a pyridazinyl group, a triazinyl         group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, an isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group, and an         azacarbazolyl group, each substituted with at least one selected         from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amidino group, a hydrazino group, a         hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a         phenyl group, a biphenyl group, a terphenyl group, a naphthyl         group, a fluorenyl group, a spiro-bifluorenyl group, a         benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         perylenyl group, a pentaphenyl group, a hexacenyl group, a         pentacenyl group, a thiophenyl group, a furanyl group, a         carbazolyl group, an indolyl group, an isoindolyl group, a         benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl         group, a dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl         group, a pyrimidinyl group, a pyridazinyl group, a triazinyl         group, a quinolinyl group, an isoquinolinyl group, a         benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl         group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl         group, a phenanthridinyl group, an acridinyl group, a         phenanthrolinyl group, a phenazinyl group, a benzimidazolyl         group, an isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group, and an         azacarbazolyl group; and     -   —S(═O)₂(Q₆₀₁) and —P(═O)(Q₆₀₁)(Q₆₀₂), and     -   Q₆₀₁ and Q₆₀₂ are the same as described herein above.

The electron transport region may include at least one compound selected from Compounds ET1 to ET42, but embodiments of the present disclosure are not limited thereto:

In one or more embodiments, the electron transport region may include at least one compound selected from 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), Alq₃, BAlq, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ), and NTAZ:

Thicknesses of the buffer layer, the hole blocking layer, and the electron control layer may each be in a range of about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å. When the thicknesses of the buffer layer, the hole blocking layer, and the electron control layer are within these ranges, the electron transport region may have excellent hole blocking characteristics or electron control characteristics without a substantial increase in driving voltage.

A thickness of the electron transport layer may be in a range of about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. When the thickness of the electron transport layer is within the range described herein above, the electron transport layer may have suitable or satisfactory electron transport characteristics without a substantial increase in driving voltage.

The electron transport region (for example, the electron transport layer in the electron transport region) may further include, in addition to the materials described herein above, a metal-containing material.

The metal-containing material may include at least one selected from alkali metal complex and alkaline earth-metal complex. The alkali metal complex may include a metal ion selected from a Li ion, a Na ion, a K ion, a Rb ion, and a Cs ion, and the alkaline earth-metal complex may include a metal ion selected from a Be ion, a Mg ion, a Ca ion, a Sr ion, and a Ba ion. A ligand coordinated with the metal ion of the alkali metal complex or the alkaline earth-metal complex may be selected from a hydroxy quinoline, a hydroxy isoquinoline, a hydroxy benzoquinoline, a hydroxy acridine, a hydroxy phenanthridine, a hydroxy phenyloxazole, a hydroxy phenylthiazole, a hydroxy diphenyloxadiazole, a hydroxy diphenylthiadiazole, a hydroxy phenylpyridine, a hydroxy phenylbenzimidazole, a hydroxy phenylbenzothiazole, a bipyridine, a phenanthroline, and a cyclopentadiene, but embodiments of the present disclosure are not limited thereto.

For example, the metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (lithium quinolate, LiQ) or ET-D2:

The electron transport region may include an electron injection layer that facilitates electron injection from the second electrode 190. The electron injection layer may directly contact the second electrode 190.

The electron injection layer may have i) a single-layered structure including a single layer including a single material, ii) a single-layered structure including a single layer including a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including a plurality of different materials.

The electron injection layer may include an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combinations thereof.

The alkali metal may be selected from Li, Na, K, Rb, and Cs. In one embodiment, the alkali metal may be Li, Na, or Cs. In one or more embodiments, the alkali metal may be Li or Cs, but embodiments of the present disclosure are not limited thereto.

The alkaline earth metal may be selected from Mg, Ca, Sr, and Ba.

The rare earth metal may be selected from Sc, Y, Ce, Tb, Yb, and Gd.

The alkali metal compound, the alkaline earth-metal compound, and the rare earth metal compound may be selected from oxides and halides (for example, fluorides, chlorides, bromides, or iodides) of the alkali metal, the alkaline earth-metal, and the rare earth metal.

The alkali metal compound may be selected from alkali metal oxides, such as Li₂O, Cs₂O, or K₂O, and alkali metal halides, such as LiF, NaF, CsF, KF, LiI, NaI, CsI, or KI. In one embodiment, the alkali metal compound may be selected from LiF, Li₂O, NaF, LiI, NaI, CsI, and KI, but embodiments of the present disclosure are not limited thereto.

The alkaline earth-metal compound may be selected from alkaline earth-metal oxides, such as BaO, SrO, CaO, Ba_(x)Sr_(1-x)O (0<x<1), or Ba_(x)Ca_(1-x)P (0<x<1). In one embodiment, the alkaline earth-metal compound may be selected from BaO, SrO, and CaO, but embodiments of the present disclosure are not limited thereto.

The rare earth metal compound may be selected from YbF₃, ScF₃, SC₂O₃, Y₂O₃, Ce₂O₃, GdF₃, and TbF₃. In one embodiment, the rare earth metal compound may be selected from YbF₃, ScF₃, TbF₃, YbI₃, ScI₃, and TbI₃, but embodiments of the present disclosure are not limited thereto.

The alkali metal complex, the alkaline earth-metal complex, and the rare earth metal complex may include an ion of alkali metal, alkaline earth-metal, and rare earth metal as described herein above, and a ligand coordinated with a metal ion of the alkali metal complex, the alkaline earth-metal complex, or the rare earth metal complex may be selected from hydroxy quinoline, hydroxy isoquinoline, hydroxy benzoquinoline, hydroxy acridine, hydroxy phenanthridine, hydroxy phenyloxazole, hydroxy phenylthiazole, hydroxy diphenyloxadiazole, hydroxy diphenylthiadiazole, hydroxy phenylpyridine, hydroxy phenylbenzimidazole, hydroxy phenylbenzothiazole, bipyridine, phenanthroline, and cyclopentadiene, but embodiments of the present disclosure are not limited thereto.

The electron injection layer may include (or consist of) an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combinations thereof, as described herein above. In one or more embodiments, the electron injection layer may further include an organic material. When the electron injection layer further includes an organic material, an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combinations thereof may be homogeneously or non-homogeneously dispersed in a matrix including the organic material.

A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å. When the thickness of the electron injection layer is within the range described herein above, the electron injection layer may have suitable or satisfactory electron injection characteristics without a substantial increase in driving voltage.

Second Electrode 190

The second electrode 190 may be on the organic layer 150 having such a structure. The second electrode 190 may be a cathode which is an electron injection electrode, and in this regard, a material for forming the second electrode 190 may be selected from metal, an alloy, an electrically conductive compound, and a combination thereof, which have a relatively low work function.

The second electrode 190 may include at least one selected from lithium (Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), ITO, and IZO, but embodiments of the present disclosure are not limited thereto. The second electrode 190 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

The second electrode 190 may have a single-layered structure, or a multi-layered structure including two or more layers.

In one embodiment, the first electrode 110 may be an anode, the second 190 electrode may be a cathode, and the organic layer 150 may further include a hole transport region between the first electrode 110 and the emission layer and an electron transport region between the emission layer and the second electrode 190. The hole transport region may include a hole injection layer, a hole transport layer, an emission auxiliary layer, an electron blocking layer, or any combination thereof, the electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

In one embodiment, the hole transport region of the organic light-emitting device may include a p-dopant, and the p-dopant may have a LUMO energy level of about −3.5 eV or less.

In one or more embodiments, the hole transport region may include an hole blocking layer, which includes a carbazole-containing compound. In one or more embodiments, the electron blocking layer may be in direct contact with the emission layer.

In one embodiment, the electron transport region of the organic light-emitting device may further include a metal-containing material, such as an alkali metal, alkaline earth metal, a rare earth metal, an alkali metal compound, alkaline earth metal Compound, a rare earth metal Compound, an alkali metal complex, alkaline earth metal complex, a rare earth metal complex, or any combination thereof.

In one embodiment, the electron transport region may include a hole blocking layer, and the hole blocking layer may include a dibenzothiophene-containing compound. In one or more embodiments, the hole blocking layer may be in direct contact with the emission layer.

Description of FIGS. 2 to 4

FIG. 2 is a schematic view of an organic light-emitting device 20 according to an embodiment. The organic light-emitting device 20 includes a first capping layer 210, the first electrode 110, the organic layer 150, and the second electrode 190, which are sequentially stacked in this stated order. FIG. 3 is a schematic view of an organic light-emitting device 30 according to an embodiment. The organic light-emitting device 30 includes the first electrode 110, the organic layer 150, the second electrode 190, and a second capping layer 220, which are sequentially stacked in this stated order. FIG. 4 is a schematic view of an organic light-emitting device 40 according to an embodiment. The organic light-emitting device 40 includes the first capping layer 210, the first electrode 110, the organic layer 150, the second electrode 190, and the second capping layer 220, which are sequentially stacked in this stated order.

Regarding FIGS. 2 to 4 , the first electrode 110, the organic layer 150, and the second electrode 190 may be understood by referring to the description presented in connection with FIG. 1 .

In the organic layer 150 of each of the organic light-emitting devices 20 and 40, light generated in an emission layer may pass through the first electrode 110 and the first capping layer 210 toward the outside, wherein the first electrode 110 may be a semi-transmissive electrode or a transmissive electrode. In the organic layer 150 of each of the organic light-emitting devices 30 and 40, light generated in an emission layer may pass through the second electrode 190 and the second capping layer 220 toward the outside, wherein the second electrode 190 may be a semi-transmissive electrode or a transmissive electrode.

The first capping layer 210 and the second capping layer 220 may increase external luminescence efficiency according to the principle of constructive interference.

The first capping layer 210 and the second capping layer 220 may each independently be an organic capping layer including an organic material, an inorganic capping layer including an inorganic material, or a composite capping layer including an organic material and an inorganic material.

At least one selected from the first capping layer 210 and the second capping layer 220 may each independently include at least one material selected from carbocyclic compounds, heterocyclic compounds, amine-based compounds, porphyrine derivatives, phthalocyanine derivatives, a naphthalocyanine derivatives, alkali metal complexes, and alkaline earth metal complexes. The carbocyclic compound, the heterocyclic compound, and the amine-based compound may be optionally substituted with a substituent containing at least one element selected from O, N, S, Se, Si, F, Cl, Br, and I. In one embodiment, at least one selected from the first capping layer 210 and the second capping layer 220 may each independently include an amine-based compound.

In one embodiment, at least one selected from the first capping layer 210 and the second capping layer 220 may each independently include the compound represented by Formula 201 or the compound represented by Formula 202.

In one or more embodiments, at least one selected from the first capping layer 210 and the second capping layer 220 may each independently include a compound selected from Compounds HT28 to HT33 and Compounds CP1 to CP5, but embodiments of the present disclosure are not limited thereto:

Hereinbefore, the organic light-emitting device according to an embodiment has been described in connection with FIGS. 1 to 4 , but embodiments of the present disclosure are not limited thereto.

Layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region may be formed in a set or certain region by using one or more suitable methods selected from vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, and laser-induced thermal imaging.

When layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region are formed by vacuum deposition, the deposition may be performed at a deposition temperature of about 100° C. to about 500° C., a vacuum degree of about 10⁻⁸ torr to about 10⁻³ torr, and a deposition speed of about 0.01 Å/sec to about 100 Å/sec by taking into account a material to be included in a layer to be formed, and the structure of a layer to be formed.

When layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region are formed by spin coating, the spin coating may be performed at a coating speed of about 2,000 rpm to about 5,000 rpm and at a heat treatment temperature of about 80° C. to 200° C. by taking into account a material to be included in a layer to be formed, and the structure of a layer to be formed.

General Definition of at Least Some of the Substituents

The term “C₁-C₆₀ alkyl group,” as used herein, refers to a linear or branched aliphatic saturated hydrocarbon monovalent group having 1 to 60 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isoamyl group, and a hexyl group. The term “C₁-C₆₀ alkylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₁-C₆₀ alkyl group.

The term “C₂-C₆₀ alkenyl group,” as used herein, refers to a hydrocarbon group having at least one carbon-carbon double bond at a main chain (e.g., in the middle) or at a terminal end (e.g., at the terminus) of the C₂-Coo alkyl group, and examples thereof include an ethenyl group, a propenyl group, and a butenyl group.

The term “C₂-C₆₀ alkenylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group,” as used herein, refers to a hydrocarbon group having at least one carbon-carbon triple bond at a main chain (e.g., in the middle) or at a terminal end (e.g., at the terminus) of the C₂-C₆₀ alkyl group, and examples thereof include an ethynyl group, and a propynyl group. The term “C₂-C₆₀ alkynylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₂-C₆₀ alkynyl group.

The term “C₁-C₆₀ alkoxy group,” as used herein, refers to a monovalent group represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group), and examples thereof include a methoxy group, an ethoxy group, and an isopropyloxy group.

The term “C₃-C₁₀ cycloalkyl group,” as used herein, refers to a monovalent saturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term “C₃-C₁₀ cycloalkylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group,” as used herein, refers to a monovalent monocyclic group having at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom and 1 to 10 carbon atoms, and examples thereof include a 1,2,3,4-oxatriazolidinyl group, a tetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term “C₁-C₆₀ heterocycloalkylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group,” as used herein, refers to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one carbon-carbon double bond in the ring thereof and no aromaticity (e.g., is not aromatic), and examples thereof include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀ cycloalkenylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group,” as used herein, refers to a monovalent monocyclic group that has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom, 1 to 10 carbon atoms, and at least one carbon-carbon double bond in its ring. Non-limiting examples of the C₁-C₁₀ heterocycloalkenyl group include a 4,5-dihydro-1,2,3,4-oxatriazolyl group, a 2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylene group,” as used herein, refers to a divalent group having substantially the same structure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group,” as used herein, refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and the term “C₆-C₆₀ arylene group,” as used herein, refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Non-limiting examples of the C₆-C₆₀ aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylene group each include two or more rings, the rings may be fused to each other (e.g., combined together).

The term “C₁-C₆₀ heteroaryl group,” as used herein, refers to a monovalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom, in addition to 1 to 60 carbon atoms.

The term “C₁-C₆₀ heteroarylene group,” as used herein, refers to a divalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom, in addition to 1 to 60 carbon atoms. Non-limiting examples of the C₁-C₆₀ heteroaryl group include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group. When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group each include two or more rings, the rings may be condensed with each other (e.g., combined together).

The term “C₆-C₆₀ aryloxy group,” as used herein, indicates —OA₁₀₂ (wherein A₁₀₂ is the C₆-C₆₀ aryl group), and the term “C₆-C₆₀ arylthio group,” as used herein, indicates —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group).

The term “C₁-C₆₀ heteroaryloxy group,” as used herein, refers to —OA₁₀₄ (wherein A₁₀₄ is the C₁-C₆₀ heteroaryl group), and the term “C₁-C₆₀ heteroarylthio group,” as used herein, indicates —SA₁₀₅ (wherein A₁₀₅ is the C₁-C₆₀ heteroaryl group).

The term “monovalent non-aromatic condensed polycyclic group,” as used herein, refers to a monovalent group (for example, having 8 to 60 carbon atoms) having two or more rings condensed with each other (e.g., combined together), only carbon atoms as ring-forming atoms, and no aromaticity in its entire molecular structure (e.g., the entire molecular structure is not aromatic). An example of the monovalent non-aromatic condensed polycyclic group is a fluorenyl group. The term “divalent non-aromatic condensed polycyclic group,” as used herein, refers to a divalent group having substantially the same structure as the monovalent non-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group,” as used herein, refers to a monovalent group (for example, having 1 to 60 carbon atoms) having two or more rings condensed to each other (e.g., combined together), at least one heteroatom selected from N, O, Si, P, and S, other than carbon atoms, as a ring-forming atom, and no aromaticity in its entire molecular structure (e.g., the entire molecular structure is not aromatic). An example of the monovalent non-aromatic condensed heteropolycyclic group is a carbazolyl group. The term “divalent non-aromatic condensed heteropolycyclic group,” as used herein, refers to a divalent group having substantially the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

The term “C₅-C₆₀ carbocyclic group,” as used herein, refers to a monocyclic or polycyclic group having 5 to 60 carbon atoms in which a ring-forming atom is a carbon atom only. The term “C₅-C₆₀ carbocyclic group,” as used herein, refers to an aromatic carbocyclic group or a non-aromatic carbocyclic group. The Cs-Coo carbocyclic group may be a ring, such as benzene, a monovalent group, such as a phenyl group, or a divalent group, such as a phenylene group. In one or more embodiments, depending on the number of substituents connected to the Cs-Coo carbocyclic group, the C₅-C₆₀ carbocyclic group may be a trivalent group or a quadrivalent group.

The term “C₁-C₆₀ heterocyclic group,” as used herein, refers to a group having substantially the same structure as the Cs-Coo carbocyclic group, except that as a ring-forming atom, at least one heteroatom selected from N, O, Si, P, and S is used in addition to carbon (the number of carbon atoms may be in a range of 1 to 60).

In the present specification, at least one substituent of the substituted C₅-C₆₀ carbocyclic group, the substituted C₁-C₆₀ heterocyclic group, the substituted C₁-C₂₀ alkylene group, the substituted C₂-C₂₀ alkenylene group, the substituted C₃-C₁ cycloalkylene group, the substituted C₁-C₁₀ heterocycloalkylene group, the substituted C₃-C₁₀ cycloalkenylene group, the substituted C₁-C₁₀ heterocycloalkenylene group, the substituted C₆-C₆₀ arylene group, the substituted C₁-C₆₀ heteroarylene group, the substituted divalent non-aromatic condensed polycyclic group, the substituted divalent non-aromatic condensed heteropolycyclic group, the substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substituted C₁-C₆₀ heteroaryloxy group, the substituted C₁-C₆₀ heteroarylthio group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from:

-   -   deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazino group, a hydrazono         group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀         alkynyl group, and a C₁-C₆₀ alkoxy group;     -   a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, and a C₁-C₆₀ alkoxy group, each substituted with at least         one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,         a cyano group, a nitro group, an amidino group, a hydrazino         group, a hydrazono group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀         heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀         heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy         group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a         monovalent non-aromatic condensed polycyclic group, a monovalent         non-aromatic condensed heteropolycyclic group,         —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁),         —S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂);     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁a cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group;     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group, each substituted with at least         one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,         a cyano group, a nitro group, an amidino group, a hydrazino         group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl         group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀         cycloalkyl group, a C₁-C₆₀ heterocycloalkyl group, a C₃-C₁₀         cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀         aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a         C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed         polycyclic group, a monovalent non-aromatic condensed         heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂),         —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂);         and     -   —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),         —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and     -   Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each independently be         selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl         group, a cyano group, a nitro group, an amidino group, a         hydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a         C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy         group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl         group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl         group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a         monovalent non-aromatic condensed polycyclic group, a monovalent         non-aromatic condensed heteropolycyclic group, a biphenyl group,         and a terphenyl group.

The term “Ph,” as used herein, represents a phenyl group, the term “Me,” as used herein, represents a methyl group, the term “Et,” as used herein, represents an ethyl group, the term “ter-Bu” or “Bu^(t),” as used herein, represents a tert-butyl group, and the term “OMe,” as used herein, represents a methoxy group.

The term “biphenyl group,” as used herein, refers to a “phenyl group substituted with a phenyl group. The “biphenyl group” is a “substituted phenyl group” having a “C₆-C₆₀ aryl group” as a substituent.

The term “terphenyl group,” as used herein, refers to a “phenyl group substituted with a biphenyl group. The “terphenyl group” is a “phenyl group” having, as a substituent, a “C₆-C₆₀ aryl group substituted with a C₆-C₆₀ aryl group”.

* and *′, as used herein, unless defined otherwise, each refer to a binding site to a neighboring atom in a corresponding formula.

Hereinafter, a compound according to embodiments and an organic light-emitting device according to embodiments will be described in more detail with reference to Synthesis Examples and Examples. The expression “B was used instead of A” used in describing Synthesis Examples means that an identical number of molar equivalents of B was used in place of molar equivalents of A.

EXAMPLES Evaluation 1: Energy Level Measurement

A thin film formed by depositing each of the Compounds shown in Table 1 to a thickness of 300 Å was cooled to a low temperature (4K), and a photoluminescence spectrum was measured by using a photoluminescence measurement apparatus. The photoluminescence spectrum was compared with a general room-temperature photoluminescence spectrum, and peaks observed only at a low temperature were analyzed. From the analysis, triplet (T1) energy levels and ΔE_(st) were measured. Results thereof are shown in Table 1.

Triplet energy at an onset wavelength means triplet energy at a position at which the photoluminescence spectrum started, and triplet energy was calculated as triplet energy at a position intersecting with a wavelength axis of a function obtained by plotting the photoluminescence spectrum with a quadratic function.

TABLE 1 Compound T1_(onset)(eV) T1_(max)(eV) ΔEst (eV) Compound H62 3.07 2.7 0.45 Compound 12-12 2.83 2.72 0.14 Compound A 2.792 2.698 0.119 Compound B 3.13 3.02 0.48 Compound C 1.9 1.8 0.9 Compound D 3.21 3.00 0.47 Compound E 2.54 2.48 0.40

Example 1

A Corning 15 Ω/cm² (1,200 Å) ITO glass substrate (anode) was cut to a size of 50 mm×50 mm×0.7 mm, sonicated with isopropyl alcohol and pure water each for 5 minutes, and then cleaned by exposure to ultraviolet rays and ozone for 30 minutes. The ITO glass substrate was provided to a vacuum deposition apparatus.

2-TNATA was vacuum-deposited on the ITO glass substrate to form a hole injection layer having a thickness of 600 Å, and HAT-CN was vacuum-deposited on the hole injection layer to form a hole transport layer having a thickness of 300 Å.

Compound H62 (host) and Compound 12-12 (dopant) were co-deposited on the hole transport layer to a weight ratio of 95:5 to form an emission layer having a thickness of 300 Å.

Then, ET1 was vacuum-deposited on the emission layer to form an electron transport layer having a thickness of 300 Å. Yb was vacuum-deposited on the electron transport layer to form an electron injection layer having a thickness of 10 Å, and Al was vacuum-deposited to form a cathode having a thickness of 3,000 Å, thereby completing the manufacture of an organic light-emitting device.

Comparative Examples 1 to 3

Organic light-emitting devices were manufactured in substantially the same manner as in Example 1, except that Compounds shown in Table 2 were each used in forming an emission layer.

Evaluation Example 2

The driving voltage, external quantum efficiency, lifespan (LT₅₀), and color purity of the organic light-emitting devices manufactured according to Example 1 and Comparative Examples 1 to 3 were measured at a current density of 10 mA/cm² by using the following methods. Results thereof are shown in Table 2.

-   -   Color coordinates: Power was supplied by a current-voltage meter         (Keithley SMU 236), and color coordinates were measured by using         a luminance meter PR650.     -   Luminance: Power was supplied by a current-voltage meter         (Keithley SMU 236), and luminance was measured by using a         luminance meter PR650.     -   Efficiency: Power was supplied by a current-voltage meter         (Keithley SMU 236), and efficiency was measured by using a         luminance meter PR650.

TABLE 2 Driving External Color Emission layer voltage quantum LT₅₀ coordinates Host Dopant (V) efficiency (%) (hr) CIEx CIEy Example 1 Compound Compound 12-12 3.7 20 250 0.13 0.15 H62 Comparative Compound Compound A 3.7 12  50 0.12 0.13 Example 1 H62 Comparative Compound Compound C 3.7 11  45 0.13 0.14 Example 2 B Comparative Compound Compound E 3.7 11  60 0.13 0.15 Example 3 D

Referring to Tables 1 and 2, it can be seen that the organic light-emitting device according to one or more embodiments satisfies Equations 1-1 and 1-2 and has excellent external quantum efficiency and improved lifespan, as compared with those of the organic light-emitting devices of Comparative Examples 1 to 3.

In addition, it can be seen that the organic light-emitting device according to one or more embodiments emit blue light.

For example, the organic light-emitting device according to one or more embodiments has excellent external quantum efficiency and improved lifespan characteristics and is suitable for blue light emission.

The organic light-emitting device may have high external quantum efficiency and a long lifespan.

It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should be considered as available for other similar features or aspects in other embodiments.

It will be understood that, although the terms “first,” “second,” “third,” etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section described above could be termed a second element, component, region, layer or section, without departing from the spirit and scope of the present disclosure.

Spatially relative terms, such as “beneath,” “below,” “lower,” “under,” “above,” “upper,” and the like, may be used herein for ease of explanation to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or in operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” or “under” other elements or features would then be oriented “above” the other elements or features. Thus, the example terms “below” and “under” can encompass both an orientation of above and below. The device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should be interpreted accordingly.

As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

As used herein, the terms “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. Further, the use of “may” when describing embodiments of the present disclosure refers to “one or more embodiments of the present disclosure.” As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively. Also, the term “exemplary” is intended to refer to an example or illustration.

Also, any numerical range recited herein is intended to include all sub-ranges of the same numerical precision subsumed within the recited range. For example, a range of “1.0 to 10.0” is intended to include all subranges between (and including) the recited minimum value of 1.0 and the recited maximum value of 10.0, that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein, and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited herein.

While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims, and equivalents thereof. 

What is claimed is:
 1. An organic light-emitting device comprising: a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode and comprising an emission layer, wherein the emission layer comprises a first host, a second host, a first dopant and a second dopant, the first host is a compound comprising a hole transport moiety, the second host is a compound comprising an electron transport moiety, the first host and the second host form an exciplex, the first host and the first dopant each satisfy Equations 1-1 and 1-2, and the second dopant is a fluorescent dopant or a delayed fluorescent dopant satisfying Equation 3-3: T1(H1)_(onset) ≥T1(D1)_(onset)  Equation 1-1 T1(H1)_(max) ≤T1(D1)_(max),  Equation 1-2 wherein, in Equations 1-1 and 1-2, T1(H1)_(onset) is triplet energy at an onset wavelength (λ_(onset)) of the first host, T1(D1)_(onset) is triplet energy at an onset wavelength of the first dopant, T1(H1)_(max) is triplet energy at a maximum emission wavelength (Amax) of the first host, and T1(D1)_(max) is triplet energy at a maximum emission wavelength of the first dopant, S1(D2)−T1(D2)≤0.3 eV,  Equation 3-3 wherein, in Equation 3-3, S1(D2) is a singlet energy of the second dopant, and T1(D2) is a triplet energy of the second dopant.
 2. The organic light-emitting device of claim 1, wherein the first host and the first dopant each satisfy Equation 2-1: T1(H1)_(max) ≤T1(D1)_(max) ≤T1(H1)_(max)+0.5 eV,  Equation 2-1 wherein, in Equation 2-1, T1(H1)_(max) is triplet energy at the maximum emission wavelength of the first host, T1(D1)_(max) is triplet energy at the maximum emission wavelength of the first dopant.
 3. The organic light-emitting device of claim 1, wherein the first host is a hole transport compound that does not comprise an electron transport moiety.
 4. The organic light-emitting device of claim 1, wherein the first host and the first dopant form an exciplex.
 5. The organic light-emitting device of claim 1, wherein the first host satisfies Equation 3-1: S1(H1)−T1(H1)≤0.3 eV,  Equation 3-1 wherein, in Equation 3-1, S1(H1) is a singlet energy of the first host, and T1(H1) is a triplet energy of the first host.
 6. The organic light-emitting device of claim 1, wherein the second host is represented by Formula 2:

wherein, in Formula 2, X₂₁ is N or C(R₂₁), X₂₂ is N or C(R₂₂), X₂₃ is N or C(R₂₃), X₂₄ is N or C(R₂₄), X₂₅ is N or C(R₂₅), and X₂₆ is N or C(R₂₆), wherein at least one selected from X₂₁ to X₂₆ is N, R₂₁ to R₂₆ are each independently selected from hydrogen, deuterium, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, and at least one selected from R₂₁ to R₂₆ is selected from a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.
 7. The organic light-emitting device of claim 1, wherein the first dopant is a fluorescent dopant or a delayed fluorescent dopant satisfying Equation 3-2: S1(D1)−T1(D1)≤0.3 eV,  Equation 3-2 wherein, in Equation 3-2, S1(D1) is a singlet energy of the first dopant, and T1(D1) is a triplet energy of the first dopant.
 8. The organic light-emitting device of claim 1, wherein the emission layer emits blue light having a maximum emission wavelength of about 440 nm or more and about 490 nm or less.
 9. The organic light-emitting device of claim 1, wherein the amount of the first host in the emission layer is larger than the amount of the first dopant.
 10. The organic light-emitting device of claim 1, wherein a ratio of an emission component emitted from the first dopant to a total emission component emitted from the emission layer is 80% or more.
 11. The organic light-emitting device of claim 1, wherein the first dopant and the second dopant are each independently a heterocyclic compound represented by Formula 11: (Ar₁)_(n1)—(L₁)_(m1)—(Ar₂)_(n2),  Formula 11 wherein, in Formula 11, L₁ is a C₅-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group, n1 and n2 are each independently an integer from 0 to 3, and satisfy n1+n2≥1, m1 is an integer from 0 to 5, and Ar₁ and Ar₂ are each independently a group represented by Formula 11A or 11B:

wherein, in Formulae 11A and 11B, Y₁ and Y₂ are each independently selected from a single bond, —O—, —S—, —C(R_(10a))(R_(10b))—, —N(R_(10a))—, Si(R_(10a))(R_(10b))—, —C(═O)—, —S(═O)₂, —B(R_(10a))—, —P(R_(10a))—, and —P(═O)(R_(10a))(R_(10b))—, k1 and k2 are each independently 0 or 1, and satisfy k1+k2≥1, CY₁ and CY₂ are each independently a C₅-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group, X₁ to X₃ are each independently C or N, when X₁ to X₃ are each C, at least one of R₃₀(s) is a cyano group, R_(10a), R_(10b), R₁₀, R₂₀, and R₃₀ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or unsubstituted C₁-C₆₀ heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂), a10 and a20 are each independently an integer from 1 to 10, a30 is an integer from 1 to 6, two or more of R_(10a), R_(10b), R₁₀, and R₂₀ are optionally linked to form a substituted or unsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclic group, when a30 is 2 or more, two or more R₃₀(s) are optionally linked to form a substituted or unsubstituted Cs-Coo carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclic group, at least one selected from R_(10a), R_(10b), R₁₀, and R₂₀ in Formula 11A is a binding site to L₁ or Ar₁, at least one of R₃₀(s) in Formula 11B is a binding site to L₁ or Ar₁, at least one substituent of the substituted Cs-Coo carbocyclic group, the substituted C₁-C₆₀ heterocyclic group, the substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substituted C₁-C₆₀ heteroaryloxy group, the substituted C₁-C₆₀ heteroarylthio group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —C₁, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₁₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂); and —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₁₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group.
 12. The organic light-emitting device of claim 11, wherein at least one selected from Ar₁ and Ar₂ is a group represented by one selected from Formulae 11(1) to 11(4):

wherein, in Formulae 11(1) to 11(4), Y₁₁ to Y₁₄ are each independently selected from a single bond, —O—, —S—, —C(R₁₅)(R₁₆)—, —N(R₁₅)—, Si(R₁₅)(R₁₆)—, —C(═O)₂—, —S(═O)₂—, —B(R₁₅)—, —P(R₁₅)—, and —P(═O)(R₁₅)(R₁₆)—, Y₁₅ is N, B, or P, CY₁₁ to CY₁₄ are each independently selected from a benzene group, a naphthalene group, a carbazole group, a dibenzofuran group, a dibenzothiophene group, and a dibenzosilole group, R₁₁ to R₁₆ are each independently selected from a binding site to Li₁ or Ar₁, hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or unsubstituted C₁-C₆₀ heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂), at least two substituents selected from R₁₁ to R₁₆ are optionally linked to form a substituted or unsubstituted C₅-Coo carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclic group, at least one selected from R₁₁ to R₁₆ is a binding site to L₁ or Ar₁, a11 to a14 are each independently an integer from 1 to 6, and Q₁ to Q₃ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a biphenyl group, and a terphenyl group.
 13. The organic light-emitting device of claim 11, wherein L₁ is a single bond or a group represented by one selected from Formulae 3-1 to 3-35:

wherein, in Formulae 3-1 to 3-35, X₁₁ is *—O—*′, *—S—*′, or *—N(Z₁₅)—*′, Z₁ to Z₄, Z₁₁, Z₁₂, and Z₁₅ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a triazinyl group, a benzimidazolyl group, a phenanthrolinyl group, and —Si(Q₃₁)(Q₃₂)(Q₃₃), Q₃₁ to Q₃₃ are each independently selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group, d2 is an integer from 0 to 2, d3 is an integer from 0 to 3, d4 is an integer from 0 to 4, d5 is an integer from 0 to 5, d6 is an integer from 0 to 6, d8 is an integer from 0 to 8, and * and *′ each indicate a binding site to a neighboring atom.
 14. The organic light-emitting device of claim 11, wherein R_(10a), R_(10b), R₁₀, R₂₀, and R₃₀ are each independently selected from: hydrogen, deuterium, —F, —Cl, —Br, —I, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an ethenyl group, a propenyl group, a butenyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, an isobutoxy group, and a tert-butoxy group; and a group represented by one selected from Formulae 5-1 to 5-26 and 6-1 to 6-55:

wherein, in Formulae 5-1 to 5-26 and 6-1 to 6-55, Y₃, and Y₃₂ are O, S, C(Z₃₃)(Z₃₄), N(Z₃₃), or Si(Z₃₃)(Z₃₄), Z₃₁ to Z₃₄ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkenyl group, a C₁-C₂₀ alkynyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyridinyl group, a pyrimidinyl group, a carbazolyl group, and a triazinyl group, e2 is 1 or 2, e3 is an integer from 1 to 3, e4 is an integer from 1 to 4, e5 is an integer from 1 to 5, e6 is an integer from 1 to 6, e7 is an integer from 1 to 7, e9 is an integer from 1 to 9, and * indicates a binding site to a neighboring atom.
 15. The organic light-emitting device of claim 1, wherein the second dopant is a fluorescent dopant.
 16. The organic light-emitting device of claim 1, wherein the fluorescent dopant includes a compound represented by Formula 501, or selected from the following compounds:

in Formula 501, Ar₅₀₁ is a substituted or unsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclic group, L₅₀₁ to L₅₀₃ are each independently selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group, xd1 to xd3 are each independently an integer from 0 to 3, R₅₀₁ and R₅₀₂ are each independently selected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, and xd4 is an integer from 1 to
 6. 17. The organic light-emitting device of claim 1, wherein the first electrode is an anode, the second electrode is a cathode, the organic layer further comprises a hole transport region between the first electrode and the emission layer and an electron transport region between the emission layer and the second electrode, the hole transport region comprises a hole injection layer, a hole transport layer, an emission auxiliary layer, an electron blocking layer, or any combination thereof, and the electron transport region comprises a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, an electron injection layer, or any combination thereof.
 18. The organic light-emitting device of claim 17, wherein the hole transport region comprises a p-dopant, and the p-dopant has a lowest unoccupied molecular orbital (LUMO) energy level of about −3.5 eV or less.
 19. The organic light-emitting device of claim 17, wherein the electron transport region comprises a metal-containing material.
 20. An electronic apparatus comprising: the organic light-emitting device of claim 1; and a thin-film transistor, wherein the first electrode of the organic light-emitting device is in electrical contact with one of a source electrode and a drain electrode of the thin-film transistor. 